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Morrison SF, Cano G, Hernan SL, Chiavetta P, Tupone D. Inhibition of the hypothalamic ventromedial periventricular area activates a dynorphin pathway-dependent thermoregulatory inversion in rats. Curr Biol 2025; 35:59-76.e4. [PMID: 39626667 PMCID: PMC11706707 DOI: 10.1016/j.cub.2024.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 09/06/2024] [Accepted: 11/05/2024] [Indexed: 01/11/2025]
Abstract
To maintain core body temperature in mammals, CNS thermoregulatory networks respond to cold exposure by increasing brown adipose tissue and shivering thermogenesis. However, in hibernation or torpor, this canonical thermoregulatory response is replaced by a new, emerging paradigm, thermoregulatory inversion (TI), an alternative homeostatic state in which cold exposure inhibits thermogenesis and warm exposure stimulates thermogenesis. Here, we demonstrate that in the non-torpid rat, either exclusion of the canonical thermoregulatory integrator in the preoptic hypothalamus or inhibition of neurons in the ventromedial periventricular area (VMPeA) induces the TI state through an alternative thermoregulatory pathway. Within this pathway, we have identified a dynorphinergic input to the dorsomedial hypothalamus from the dorsolateral parabrachial nucleus that plays a critical role in mediating the cold-evoked inhibition of thermogenesis during TI. Our results reveal a novel thermosensory reflex circuit within the mammalian CNS thermoregulatory pathways and support the potential for pharmacologically inducing the TI state to elicit therapeutic hypothermia in non-hibernating species, including humans.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, USA
| | - Georgina Cano
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Shelby L Hernan
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Pierfrancesco Chiavetta
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, USA
| | - Domenico Tupone
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, USA; Department of Biomedical and Neuromotor Science, University of Bologna, Bologna 40126, Italy.
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Tupone D, Hernan S, Chiavetta P, Morrison S, Cano G. Central circuit controlling thermoregulatory inversion and torpor-like state. RESEARCH SQUARE 2023:rs.3.rs-2698203. [PMID: 36993654 PMCID: PMC10055657 DOI: 10.21203/rs.3.rs-2698203/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
To maintain core body temperature in mammals, the CNS thermoregulatory networks respond to cold exposure by increasing brown adipose tissue and shivering thermogenesis. However, in hibernation or torpor, this normal thermoregulatory response is supplanted by "thermoregulatory inversion", an altered homeostatic state in which cold exposure causes inhibition of thermogenesis and warm exposure stimulates thermogenesis. Here we demonstrate the existence of a novel, dynorphinergic thermoregulatory reflex pathway between the dorsolateral parabrachial nucleus and the dorsomedial hypothalamus that bypasses the normal thermoregulatory integrator in the hypothalamic preoptic area to play a critical role in mediating the inhibition of thermogenesis during thermoregulatory inversion. Our results indicate the existence of a neural circuit mechanism for thermoregulatory inversion within the CNS thermoregulatory pathways and support the potential for inducing a homeostatically-regulated, therapeutic hypothermia in non-hibernating species, including humans.
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Addiction and the cerebellum with a focus on actions of opioid receptors. Neurosci Biobehav Rev 2021; 131:229-247. [PMID: 34555385 DOI: 10.1016/j.neubiorev.2021.09.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/12/2021] [Accepted: 09/12/2021] [Indexed: 01/19/2023]
Abstract
Increasing evidence suggests that the cerebellum could play a role in the higher cognitive processes involved in addiction as the cerebellum contains anatomical and functional pathways to circuitry controlling motivation and saliency. In addition, the cerebellum exhibits a widespread presence of receptors, including opioid receptors which are known to play a prominent role in synaptic and circuit mechanisms of plasticity associated with drug use and development of addiction to opioids and other drugs of abuse. Further, the presence of perineural nets (PNNs) in the cerebellum which contain proteins known to alter synaptic plasticity could contribute to addiction. The role the cerebellum plays in processes of addiction is likely complex, and could depend on the particular drug of abuse, the pattern of use, and the stage of the user within the addiction cycle. In this review, we discuss functional and structural modifications shown to be produced in the cerebellum by opioids that exhibit dependency-inducing properties which provide support for the conclusion that the cerebellum plays a role in addiction.
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Mella-Raipán J, Romero-Parra J, Recabarren-Gajardo G. DARK Classics in Chemical Neuroscience: Heroin and Desomorphine. ACS Chem Neurosci 2020; 11:3905-3927. [PMID: 32568519 DOI: 10.1021/acschemneuro.0c00262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Opioids are arguably one of the most important pharmacologic classes, mainly due to their rich history, their useful and potent analgesic effects, and also, just as importantly, their "Dark Side", constituted by their reinforcing properties that have led countless of users to a spiral of addiction, biological dependence, tolerance, withdrawal syndromes, and death. Among the most significant abused and addictive known opioids are heroin and desomorphine, both synthetic derivatives of morphine that belong to the 4,5-epoxymorphinan structural chemical group of the opioid family drugs. These agents share not only structural, pharmacological, and epidemiological features but also a common geographical distribution. A drop in Afghan heroin production and its "exports" to Russia gave rise to widespread consumption of desomorphine in ex-Soviet republics during the first decade of the 21st century, representing an economical and accessible alternative for misusers to this sort of derivative. Herein we review the state of the art of history, chemistry and synthesis, pharmacology, and impact on society of these "cursed cousins".
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Affiliation(s)
- Jaime Mella-Raipán
- Instituto de Quı́mica y Bioquı́mica, Facultad de Ciencias, Universidad de Valparaı́so, Av. Gran Bretaña 1111, Valparaı́so 2360102, Chile
- Facultad de Farmacia, Centro de Investigación Farmacopea Chilena, Universidad de Valparaı́so,, Av. Gran Bretaña 1093, Valparaı́so 2360102, Chile
| | - Javier Romero-Parra
- Departamento de Quı́mica Orgánica y Fisicoquı́mica, Facultad de Ciencias Quı́micas y Farmacéuticas, Universidad de Chile, Sergio Livingstone 1007, Casilla
233, 8380492 Santiago, Chile
| | - Gonzalo Recabarren-Gajardo
- Bioactive Heterocycles Synthesis Laboratory, BHSL, Departamento de Farmacia, Facultad de Quı́mica y de Farmacia, Pontificia Universidad Católica de Chile, Casilla 306, Avda. Vicuña Mackenna 4860, Macul, 7820436 Santiago, Chile
- Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile,, Marcoleta 391, 8330024 Santiago, Chile
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Wu F, Huang Y, Yu F, Li Z, Ding CF. Effect of Transition-Metal Ions on the Conformation of Encephalin Investigated by Hydrogen/Deuterium Exchange and Theoretical Calculations. J Phys Chem B 2020; 124:101-109. [PMID: 31829598 DOI: 10.1021/acs.jpcb.9b09919] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have studied the effects of different 3d orbitals in divalent transition-metal ions [G2+ = Mn2+ (d5), Fe2+ (d6), Co2+ (d7), Ni2+ (d8), Cu2+ (d9), or Zn2+ (d10)] on the conformations of leucine encephalin (LE) and methionine encephalin (ME) in the gas phase using hydrogen/deuterium exchange mass spectrometry (HDX-MS) and theoretical calculations at the molecular level. The HDX-MS reveals a 1:1 stoichiometric monovalent complex of [LE/ME + G - H]+ and observed that the different HDX reactivities follow the trend Fe2+ < Co2+ < Ni2+ < Mn2+ < Cu2+ ≈ Zn2+ and that [ME + Mn/Cu/Zn - H]+ > [LE + Mn/Cu/Zn - H]+, while [LE + Fe/Co/Ni - H]+ > [ME + Fe/Co/Ni - H]+. We cross-correlated the collision-induced dissociation energies of the complexes with the HDX results and found that the more stable the complex, the harder it is for it to undergo HDX. Furthermore, we used theoretical calculations to optimize the favorable conformations of the complexes and found the same interaction structure of G2+ coordination with the five carbonyl oxygens of LE/ME that have different bond lengths. Finally, we calculated the proton affinity (PA) values of the optimized complexes in order to interpret the HDX observations that the higher the PA values, the more difficult it is for the complex to undergo HDX. Overall, both the experiments and the theoretical calculations show that the six metal ions have different effects on the LE/ME conformation, with the low-energy stability of the G2+ 3d orbitals corresponding to more dramatic effects on the LE/ME conformation. In addition, the hardness of the ionic acid corresponding to the fully filled Mn2+ and half-filled Zn2+ orbitals also contributes strongly to the coordination effect; the conformation effect of Fe2+/Co2+/Ni2+ on LE is greater than that on ME, whereas the conformation effect of Mn2+/Cu2+/Zn2+ on ME is greater than that on LE.
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Affiliation(s)
- Fangling Wu
- Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering , Ningbo University , Ningbo , Zhejiang 315211 , China
| | - Yandong Huang
- Department of Chemistry , Fudan University , Shanghai 200438 , China
| | - Fanzhen Yu
- Department of Chemistry , Fudan University , Shanghai 200438 , China
| | - Zhenhua Li
- Department of Chemistry , Fudan University , Shanghai 200438 , China
| | - Chuan-Fan Ding
- Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering , Ningbo University , Ningbo , Zhejiang 315211 , China
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Depienne C, Ciura S, Trouillard O, Bouteiller D, Leitão E, Nava C, Keren B, Marie Y, Guegan J, Forlani S, Brice A, Anheim M, Agid Y, Krack P, Damier P, Viallet F, Houeto JL, Durif F, Vidailhet M, Worbe Y, Roze E, Kabashi E, Hartmann A. Association of Rare Genetic Variants in Opioid Receptors with Tourette Syndrome. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2019; 9:tre-09-693. [PMID: 31824749 PMCID: PMC6878848 DOI: 10.7916/tohm.v0.693] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/15/2019] [Indexed: 01/07/2023]
Abstract
Background Genes involved in Tourette syndrome (TS) remain largely unknown. We aimed to identify genetic factors contributing to TS in a French cohort of 120 individuals using a combination of hypothesis-driven and exome-sequencing approaches. Methods We first sequenced exons of SLITRK1-6 and HDC in the TS cohort and subsequently sequenced the exome of 12 individuals harboring rare variants in these genes to find additional rare variants contributing to the disorder under the hypothesis of oligogenic inheritance. We further screened three candidate genes (OPRK1, PCDH10, and NTSR2) preferentially expressed in the basal ganglia, and three additional genes involved in neurotensin and opioid signaling (OPRM1, NTS, and NTSR1), and compared variant frequencies in TS patients and 788 matched control individuals. We also investigated the impact of altering the expression of Oprk1 in zebrafish. Results Thirteen ultrarare missense variants of SLITRK1-6 and HDC were identified in 12 patients. Exome sequencing in these patients revealed rare possibly deleterious variants in 3,041 genes, 54 of which were preferentially expressed in the basal ganglia. Comparison of variant frequencies altering selected candidate genes in TS and control individuals revealed an excess of potentially disrupting variants in OPRK1, encoding the opioid kappa receptor, in TS patients. Accordingly, we show that downregulation of the Oprk1 orthologue in zebrafish induces a hyperkinetic phenotype in early development. Discussion These results support a heterogeneous and complex genetic etiology of TS, possibly involving rare variants altering the opioid pathway in some individuals, which could represent a novel therapeutic target in this disorder.
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Affiliation(s)
- Christel Depienne
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, DE
| | - Sorana Ciura
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Oriane Trouillard
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Delphine Bouteiller
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Elsa Leitão
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, DE
| | - Caroline Nava
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,Assistance Publique Hôpitaux de Paris (AP-HP), Hôpital Pitié-Salpêtrière, Département de Génétique, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Boris Keren
- Assistance Publique Hôpitaux de Paris (AP-HP), Hôpital Pitié-Salpêtrière, Département de Génétique, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Yannick Marie
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Justine Guegan
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Sylvie Forlani
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Alexis Brice
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Mathieu Anheim
- Service de neurologie, CHU de Strasbourg, Hôpital de Hautepierre, Avenue Molière, 67200 Strasbourg Strasbourg, FR
| | - Yves Agid
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Paul Krack
- Service de Neurologie, CHU de Grenoble, Avenue Maquis du Grésivaudan, 38700 La Tronche, FR.,Center for Movement Disorders, Inselspital, University of Bern, Freiburgstrasse 18, 3010 Bern, Switzerland
| | - Philippe Damier
- Service de Neurologie, CHU de Nantes, 5 Allée de l'Île Gloriette, 44093 Nantes, FR
| | - François Viallet
- Service de Neurologie, CRHU d'Aix-en-Provence, Avenue des Tamaris, 13100 Aix-en-Provence, FR
| | - Jean-Luc Houeto
- Service de Neurologie, CHU de Poitiers, 2 Rue de la Milétrie, 86021 Poitiers, FR
| | - Franck Durif
- Service de Neurologie, CHU de Clermont-Ferrand, CHU de Clermont-Ferrand, Hôpital Gabriel Montpied, 58 rue Montalembert, 63003 Clermont-Ferrand, FR
| | - Marie Vidailhet
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,Assistance Publique Hôpitaux de Paris (APHP), Hôpital Pitié-Salpêtrière, Département de Neurologie, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Yulia Worbe
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,Assistance Publique Hôpitaux de Paris (APHP), Hôpital Pitié-Salpêtrière, Département de Neurologie, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,AP-HP, Centre de Référence National Maladie Rare 'Syndrome Gilles de la Tourette', Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Emmanuel Roze
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,AP-HP, Centre de Référence National Maladie Rare 'Syndrome Gilles de la Tourette', Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Edor Kabashi
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
| | - Andreas Hartmann
- INSERM, U 1127, CNRS UMR 7225, Faculté de Médecine de Sorbonne Université, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,Assistance Publique Hôpitaux de Paris (APHP), Hôpital Pitié-Salpêtrière, Département de Neurologie, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR.,AP-HP, Centre de Référence National Maladie Rare 'Syndrome Gilles de la Tourette', Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, FR
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Li JP, Zhang T, Gao CJ, Kou ZZ, Jiao XW, Zhang LX, Wu ZY, He ZY, Li YQ. Neurochemical features of endomorphin-2-containing neurons in the submucosal plexus of the rat colon. World J Gastroenterol 2015; 21:9936-9944. [PMID: 26379398 PMCID: PMC4566386 DOI: 10.3748/wjg.v21.i34.9936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 06/10/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the distribution and neurochemical phenotype of endomorphin-2 (EM-2)-containing neurons in the submucosal plexus of the rat colon.
METHODS: The mid-colons between the right and left flexures were removed from rats, and transferred into Kreb’s solution. For whole-mount preparations, the mucosal, outer longitudinal muscle and inner circular muscle layers of the tissues were separated from the submucosal layer attached to the submucosal plexus. The whole-mount preparations from each rat mid-colon were mounted onto seven gelatin-coated glass slides, and processed for immunofluorescence histochemical double-staining of EM-2 with calcitonin gene-related peptide (CGRP), choline acetyltransferase (ChAT), nitric oxide synthetase (NOS), neuron-specific enolase (NSE), substance P (SP) and vasoactive intestinal peptide (VIP). After staining, all the fluorescence-labeled sections were observed with a confocal laser scanning microscope. To estimate the extent of the co-localization of EM-2 with CGRP, ChAT, NOS, NSE, SP and VIP, ganglia, which have a clear boundary and neuronal cell outline, were randomly selected from each specimen for this analysis.
RESULTS: In the submucosal plexus of the mid-colon, many EM-2-immunoreactive (IR) and NSE-IR neuronal cell bodies were found in the submucosal plexus of the rat mid-colon. Approximately 6 ± 4.2 EM-2-IR neurons aggregated within each ganglion and a few EM-2-IR neurons were also found outside the ganglia. The EM-2-IR neurons were also immunopositive for ChAT, SP, VIP or NOS. EM-2-IR nerve fibers coursed near ChAT-IR neurons, and some of these fibers were even distributed around ChAT-IR neuronal cell bodies. Some EM-2-IR neuronal cell bodies were surrounded by SP-IR nerve fibers, but many long processes connecting adjacent ganglia were negative for EM-2 immunostaining. Long VIP-IR processes with many branches coursed through the ganglia and surrounded the EM-2-IR neurons. The percentages of the EM-2-IR neurons that were also positive for ChAT, SP, VIP or NOS were approximately 91% ± 2.6%, 36% ± 2.4%, 44% ± 2.5% and 44% ± 4.7%, respectively, but EM-2 did not co-localize with CGRP.
CONCLUSION: EM-2-IR neurons are present in the submucosal plexus of the rat colon and express distinct neurochemical markers.
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Stevens CW. Bioinformatics and evolution of vertebrate nociceptin and opioid receptors. VITAMINS AND HORMONES 2015; 97:57-94. [PMID: 25677768 DOI: 10.1016/bs.vh.2014.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
G protein-coupled receptors (GPCRs) are ancestrally related membrane proteins on cells that mediate the pharmacological effect of most drugs and neurotransmitters. GPCRs are the largest group of membrane receptor proteins encoded in the human genome. One of the most famous types of GPCRs is the opioid receptors. Opioid family receptors consist of four closely related proteins expressed in all vertebrate brains and spinal cords examined to date. The three classical types of opioid receptors shown unequivocally to mediate analgesia in animal models and in humans are the mu- (MOR), delta- (DOR), and kappa-(KOR) opioid receptor proteins. The fourth and most recent member of the opioid receptor family discovered is the nociceptin or orphanin FQ receptor (ORL). The role of ORL and its ligands in producing analgesia is not as clear, with both analgesic and hyperalgesic effects reported. All four opioid family receptor genes were cloned from expressed mRNA in a number of vertebrate species, and there are enough sequences presently available to carry out bioinformatic analysis. This chapter presents the results of a comparative analysis of vertebrate opioid receptors using pharmacological studies, bioinformatics, and the latest data from human whole-genome studies. Results confirm our initial hypotheses that the four opioid receptor genes most likely arose by whole-genome duplication, that there is an evolutionary vector of opioid receptor type divergence in sequence and function, and that the hMOR gene shows evidence of positive selection or adaptive evolution in Homo sapiens.
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Affiliation(s)
- Craig W Stevens
- Department of Pharmacology and Physiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA.
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Morgan MM, Reid RA, Stormann TM, Lautermilch NJ. Opioid Selective Antinociception Following Microinjection Into the Periaqueductal Gray of the Rat. THE JOURNAL OF PAIN 2014; 15:1102-1109. [DOI: 10.1016/j.jpain.2014.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 07/15/2014] [Accepted: 07/30/2014] [Indexed: 11/26/2022]
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10
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Lee PT, Chao PK, Ou LC, Chuang JY, Lin YC, Chen SC, Chang HF, Law PY, Loh HH, Chao YS, Su TP, Yeh SH. Morphine drives internal ribosome entry site-mediated hnRNP K translation in neurons through opioid receptor-dependent signaling. Nucleic Acids Res 2014; 42:13012-25. [PMID: 25361975 PMCID: PMC4245930 DOI: 10.1093/nar/gku1016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heterogeneous nuclear ribonucleoprotein K (hnRNP K) binds to the promoter region of mu-opioid receptor (MOR) to regulate its transcriptional activity. How hnRNP K contributes to the analgesic effects of morphine, however, is largely unknown. We provide evidence that morphine increases hnRNP K protein expression via MOR activation in rat primary cortical neurons and HEK-293 cells expressing MORs, without increasing mRNA levels. Using the bicistronic reporter assay, we examined whether morphine-mediated accumulation of hnRNP K resulted from translational control. We identified potential internal ribosome entry site elements located in the 5′ untranslated regions of hnRNP K transcripts that were regulated by morphine. This finding suggests that internal translation contributes to the morphine-induced accumulation of hnRNP K protein in regions of the central nervous system correlated with nociceptive and antinociceptive modulatory systems in mice. Finally, we found that down-regulation of hnRNP K mediated by siRNA attenuated morphine-induced hyperpolarization of membrane potential in AtT20 cells. Silencing hnRNP K expression in the spinal cord increased nociceptive sensitivity in wild-type mice, but not in MOR-knockout mice. Thus, our findings identify the role of translational control of hnRNP K in morphine-induced analgesia through activation of MOR.
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Affiliation(s)
- Pin-Tse Lee
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
| | - Po-Kuan Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
| | - Li-Chin Ou
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
| | - Jian-Ying Chuang
- The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei 110, Taiwan, ROC
| | - Yen-Chang Lin
- Graduate Institute of Biotechnology, Chinese Culture University, Taipei 11114, Taiwan, ROC
| | - Shu-Chun Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota, Medical School, Minneapolis, MN 55455, USA
| | - Horace H Loh
- Department of Pharmacology, University of Minnesota, Medical School, Minneapolis, MN 55455, USA
| | - Yu-Sheng Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
| | - Tsung-Ping Su
- Cellular Pathobiology Section, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County 35053, Taiwan, ROC
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11
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Schönberger M, Trauner D. A photochromic agonist for μ-opioid receptors. Angew Chem Int Ed Engl 2014; 53:3264-7. [PMID: 24519993 DOI: 10.1002/anie.201309633] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/05/2013] [Indexed: 01/09/2023]
Abstract
Opioid receptors (ORs) are widely distributed in the brain, the spinal cord, and the digestive tract and play an important role in nociception. All known ORs are G-protein-coupled receptors (GPCRs) of family A. Another well-known member of this family, rhodopsin, is activated by light through the cis/trans isomerization of a covalently bound chromophore, retinal. We now show how an OR can be combined with a synthetic azobenzene photoswitch to gain light sensitivity. Our work extends the reach of photopharmacology and outlines a general strategy for converting Family A GPCRs, which account for the majority of drug targets, into photoreceptors.
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Affiliation(s)
- Matthias Schönberger
- Department of Chemistry, Ludwig-Maximilians-University (LMU) Munich and Center of Integrated Protein Science, Butenandtstrasse 5-13, 81377 Munich (Germany)
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12
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13
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Chen M, Zhang X, Xu H, Ma X, Jiang W, Xu T. Inhibitory effect of spinal mGlu(5) receptor antisense oligonucleotide on the up-regulated expression of spinal G protein associated with chronic morphine treatment. Eur J Pharmacol 2013; 723:253-8. [PMID: 24296320 DOI: 10.1016/j.ejphar.2013.11.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/12/2013] [Accepted: 11/20/2013] [Indexed: 11/19/2022]
Abstract
Knockdown of spinal metabotropic glutamate 5 (mGlu5) receptor was shown to inhibit the development of intrathecal morphine antinociceptive tolerance. The present work was designed to evaluate the expression of spinal G-protein during morphine tolerance and knockdown of spinal mGlu5 receptor with antisense oligonucleotide (ODN). Rats were treated with saline, morphine, mGlu5 receptor antisense or mismatch ODN intrathecally. Behavioral tests were employed to test the thermal and mechanical pain thresholds. Five days later, rats were scarified and spinal expression of spinal Gαi, Gαo, Gαq and Gβ were detected. Consistent with the previous results, knockdown of spinal mGlu5 receptor could inhibit spinal morphine antinociceptive tolerance in behavioral tests (P<0.05). The mGlu5 receptor antisense ODN produced a significant reduction in mGlu5 receptor protein of about 56.6% compared with the control group (P<0.05). Expression of spinal Gαi, Gαo, Gαq and Gβ were up-regulated while morphine tolerance developed (P<0.05). Antisense ODN of spinal mGlu5 receptor, but not mismatched ODN, reduced the spinal dorsal horn levels of Gαi, Gαo, Gαs, Gαq and Gβ (P<0.05). We conclude that expression of spinal G (αi, αo, αs, αq and β) protein may be up-regulated after chronic morphine treatment which could be attenuated by knockdown of spinal mGlu5 receptor with antisense ODN.
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Affiliation(s)
- Moxi Chen
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yi Shan Road, Shanghai 200233, China
| | - Xiaoli Zhang
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yi Shan Road, Shanghai 200233, China
| | - Hao Xu
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yi Shan Road, Shanghai 200233, China
| | - Xiaqing Ma
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yi Shan Road, Shanghai 200233, China
| | - Wei Jiang
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yi Shan Road, Shanghai 200233, China.
| | - Tao Xu
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yi Shan Road, Shanghai 200233, China.
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14
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Marini P, Romanelli L, Valeri D, Cascio MG, Tucci P, Valeri P, Palmery M. The NOP receptor involvement in both withdrawal- and CCk-8-induced contracture responses of guinea pig isolated ileum after acute activation of κ-opioid receptor. Peptides 2012; 38:418-26. [PMID: 23059394 DOI: 10.1016/j.peptides.2012.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 09/27/2012] [Accepted: 09/27/2012] [Indexed: 02/06/2023]
Abstract
In isolated guinea-pig ileum (GPI), the κ-opioid acute withdrawal response is under the control of several neuronal signaling systems, including the μ-opioid, the A(1)-adenosine and the CB(1) receptors, which are involved in the inhibitory control of the κ-withdrawal response. After κ-opioid system stimulation, indirect activation of μ-opioid, A(1)-adenosine and CB(1) systems is prevented by the peptide cholecystokinin-8 (CCk-8). In the present study, we have investigated whether the NOP system is also involved in the regulation of the acute κ-withdrawal response. Interestingly, we found that in GPI preparation, the NOP system is not indirectly activated by the κ-opioid receptor stimulation, but instead this system is able by itself to directly regulate the acute κ-withdrawal response. Specifically, our results clearly highlight first the existence of an endogenous tone of the NOP system in GPI, and second that it behaves as a functional anti-opioid system. We also found that, the NOP receptor system is involved in the regulation of the CCk-8-induced contracture intensity, only when in the presence of the κ-opioid receptor stimulation. This effect seems to be regulated by an activation threshold mechanism. In conclusion, the NOP system could act as neuromodulatory system, whose action is strictly related to the modulation of both excitatory and inhibitory neurotransmitters released in GPI enteric nervous system.
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Affiliation(s)
- Pietro Marini
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK.
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15
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Prenus RV, Luscar E, Zhu ZP, Badisa RB, Goodman CB. Regulation of mammalian MOR-1 gene expression after chronic treatment with morphine. Int J Mol Med 2012; 30:1493-7. [PMID: 22992838 PMCID: PMC3789025 DOI: 10.3892/ijmm.2012.1132] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 06/05/2012] [Indexed: 11/06/2022] Open
Abstract
Morphine is an effective analgesic that acts by binding to the µ-opioid receptor (MOR) coded in the human by the OPRM1 gene. In the present study, we investigated the regulation of µ-opioid receptor (MOR-1) mRNA levels in all-trans-retinoic acid-differentiated SH-SY5Y human neuroblastoma cells under in vitro conditions with 10 µM morphine treatment for 24 h. In addition, we measured the MOR-1 levels in recombinant Chinese hamster ovary (CHO) cells, transfected with human µ-opioid receptor gene (hMOR) with 10 µM morphine treatment for 24 h. The isolated mRNA from these cells was subjected to real-time quantitative RT-PCR analysis to determine the regulation of µ-opioid receptor gene expression. It was observed that morphine treatment did not alter MOR-1 levels in undifferentiated SH-SY5Y cells compared to undifferentiated control cells. However, the MOR-1 levels in all-trans-retinoic acid-differentiated cells were significantly higher compared to the undifferentiated cells. Morphine treatment in differentiated SH-SY5Y cells caused significant downregulation of MOR-1 expression compared to the control cells. In the morphine-treated CHO cells, the hMOR-1 mRNA levels remained the same as the untreated control. Finally, pretreatment of SH-SY5Y cells with 10 µM naloxone, the antagonist of µ-opioid receptor, for 1 h significantly blocked the downregulation of MOR-1 mRNA levels with morphine treatment. These findings suggest that regulation of MOR-1 gene expression is cell-type specific after chronic morphine treatment and provide some evidence in the understanding of morphine tolerance.
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Affiliation(s)
- Rose V Prenus
- College of Pharmacy and Pharmaceutical Sciences, Florida A__AMB__M University, Tallahassee, FL 32307, USA
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Zhu ZP, Badisa RB, Palm DE, Goodman CB. Regulation of rat MOR-1 gene expression after chronic intracerebroventricular administration of morphine. Mol Med Rep 2011; 5:513-6. [PMID: 22089925 DOI: 10.3892/mmr.2011.677] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 10/19/2011] [Indexed: 11/05/2022] Open
Abstract
The µ-opioid receptor is the primary site for the action of morphine. In the present study, we investigated the regulation of the µ-opioid receptor mRNA levels in the locus ceruleus, ventral tegmental area, nucleus accumbens and hypothalamus of the rat brain following intracerebroventricular administration of morphine for 7 days. The isolated mRNA from these regions was subjected to real-time quantitative RT-PCR to determine the regulation of µ-opioid receptor gene expression. It was observed that 7 days of treatment with morphine significantly down-regulated the µ-opioid receptor mRNA levels in the hypothalamus of the brain in comparison to the control group. However, the µ-opioid receptor levels in the locus ceruleus, ventral tegmental area and nucleus accumbens regions remained the same as the control levels. Down-regulation of µ-opioid receptor mRNA levels in the hypothalamus region of the brain indicates the probable role of opioids to influence neuroendocrine function. The results further indicate that cellular adaptation for morphine tolerance is tissue-specific. These findings help us to understand the mechanism of morphine tolerance in various regions of the brain.
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Affiliation(s)
- Zhi-Ping Zhu
- College of Pharmacy and Pharmaceutical Sciences, Florida A and M University, Tallahassee, FL 32307, USA
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17
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The polypyrimidine/polypurine motif in the mouse mu opioid receptor gene promoter is a supercoiling-regulatory element. Gene 2011; 487:52-61. [PMID: 21839154 DOI: 10.1016/j.gene.2011.07.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/25/2011] [Indexed: 11/21/2022]
Abstract
The mu opioid receptor (MOR) is the principle molecular target of opioid analgesics. The polypyrimidine/polypurine (PPy/u) motif enhances the activity of the MOR gene promoter by adopting a non-B DNA conformation. Here, we report that the PPy/u motif regulates the processivity of torsional stress, which is important for endogenous MOR gene expression. Analysis by topoisomerase assays, S1 nuclease digests, and atomic force microscopy showed that, unlike homologous PPy/u motifs, the position- and orientation-induced structural strains to the mouse PPy/u element affect its ability to perturb the relaxation activity of topoisomerase, resulting in polypurine strand-nicked and catenated DNA conformations. Raman spectrum microscopy confirmed that mouse PPy/u containing-plasmid DNA molecules under the different structural strains have a different configuration of ring bases as well as altered Hoogsteen hydrogen bonds. The mouse MOR PPy/u motif drives reporter gene expression fortyfold more effectively in the sense orientation than in the antisense orientation. Furthermore, mouse neuronal cells activate MOR gene expression in response to the perturbations of topology by topoisomerase inhibitors, whereas human cells do not. These results suggest that, interestingly among homologous PPy/u motifs, the mouse MOR PPy/u motif dynamically responds to torsional stress and consequently regulates MOR gene expression in vivo.
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18
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El Maarouf A, Kolesnikov Y, Pasternak G, Rutishauser U. Removal of polysialylated neural cell adhesion molecule increases morphine analgesia and interferes with tolerance in mice. Brain Res 2011; 1404:55-62. [PMID: 21704981 DOI: 10.1016/j.brainres.2011.06.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/06/2011] [Accepted: 06/07/2011] [Indexed: 11/20/2022]
Abstract
Neurons that express high levels of polysialylated neural cell adhesion molecule (PSA-NCAM) in adult spinal substantia gelatinosa also express the μ-opioid receptor. While PSA removal from NCAM by spinal intrathecal injection of endoneuraminidase-N (endo-N) did not detectably change opioid receptor expression, morphine-induced analgesia was significantly increased. This analgesic strengthening was detected as early as 15 min after endo-N treatment and persisted for at least 7 days. In addition, the tolerance that develops with chronic morphine treatment was overcome in the absence of PSA. Interestingly, the same effects on analgesia and tolerance were also produced by selective deletion of the NCAM-180 isoform.
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Affiliation(s)
- Abderrahman El Maarouf
- Department of Cell Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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19
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Xia M, Guo V, Huang R, Shahane SA, Austin CP, Nirenberg M, Sharma SK. Inhibition of morphine-induced cAMP overshoot: a cell-based assay model in a high-throughput format. Cell Mol Neurobiol 2011; 31:901-7. [PMID: 21598037 DOI: 10.1007/s10571-011-9689-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 04/05/2011] [Indexed: 11/24/2022]
Abstract
Opiates are not only potent analgesics but also drugs of abuse mainly because they produce euphoria. Chronic use of opiates results in the development of tolerance and dependence. Dr Marshall Nirenberg's group at the National Institutes of Health (NIH) was the first to use a cellular model system of Neuroblastoma × Glioma hybrid cells (NG108-15) to study morphine addiction. They showed that opiates affect adenylyl cyclase (AC) by two opposing mechanisms mediated by the opiate receptor. Although the cellular mechanisms that cause addiction are not yet completely understood, the most observed correlative biochemical adaptation is the upregulation of AC. This model also provides the opportunity to look for compounds which could dissociate the acute effect of opiates from the delayed response, upregulation of AC, and thus lead to the discovery of non-addictive drugs. To identify small molecule compounds that can inhibit morphine-induced cAMP overshoot, we have validated and optimized a cell-based assay in a high throughput format that measures cellular cAMP production after morphine withdrawal. The assay performed well in the 1536-well plate format. The LOPAC library of 1,280 compounds was screened in this assay on a quantitative high-throughput screening (qHTS) platform. A group of compounds that can inhibit morphine-induced cAMP overshoot were identified. The most potent compounds are eight naloxone-related compounds, including levallorphan tartrate, naloxonazine dihydrochloride, naloxone hydrochloride, naltrexone hydrochloride, and naltriben methanesulfonate. The qHTS approach we used in this study will be useful in identifying novel inhibitors of morphine induced addiction from a larger scale screening.
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Affiliation(s)
- Menghang Xia
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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20
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Pappas SS, Kennedy T, Goudreau JL, Lookingland KJ. Opioid-mediated regulation of A11 diencephalospinal dopamine neurons: pharmacological evidence of activation by morphine. Neuropharmacology 2011; 61:614-21. [PMID: 21605572 DOI: 10.1016/j.neuropharm.2011.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 04/30/2011] [Accepted: 05/03/2011] [Indexed: 11/17/2022]
Abstract
Dopamine (DA) neurons of the A11 diencephalospinal system represent the sole source of DA innervation to the spinal cord in mice, serving neuromodulatory roles in the processing of nociceptive input and movement. These neurons originate in the dorso-caudal diencephalon and project axons unilaterally throughout the rostrocaudal extent of the spinal cord, terminating predominantly in the dorsal horn. The density of A11 DA axon terminals in the lumbar region is greater in males compared to females, while in both sexes the activity of neurons terminating in the thoracic spinal cord is greater than those terminating in the lumbar region. The present study was designed to test the hypothesis that A11 DA neurons are activated by opioids. To test this hypothesis, male and female mice were systemically treated with agonists or antagonists acting at the μ-opioid receptor, and spinal cord concentrations of DA and its metabolite DOPAC were determined in the thoracic and lumbar spinal cord using high performance liquid chromatography coupled with electrochemical detection. Systemic administration of the μ-opioid agonist morphine led to a dose- and time-dependent increase in spinal cord DOPAC/DA ratio (an estimate of DA neuronal activity) in both male and female mice, with greater changes occurring in the lumbar segment. Blockade of opioid receptors with the opioid antagonist naloxone reversed the stimulatory effects of morphine on A11 DA neurons in both male and female mice, but had little to no effect on the activity of these neurons when administered alone. Present findings are consistent with the conclusion that spinal cord-projecting axon terminals of A11 DA neurons are activated by opioids in both male and female mice, most likely through a dis-inhibitory mechanism.
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Affiliation(s)
- Samuel S Pappas
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
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21
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Abstract
AbstractThis study examined the presence and cellular localization of three types of opioid receptors (MOR, DOR and KOR) in five human cancer cell lines: MCF-7, MDA-MB-231, HT-29, MGH-U1 and SH-SY5Y. Expression levels of opioid receptors were measured quantitatively using real-time PCR, and the localizations of the receptors in the cells were determined by immunocytochemistry. All three types of opioid receptors were present in each of the five cell lines examined. However, three of the cell lines (MCF-7, HT-29 and SH-SY5Y) showed significantly higher levels of MOR mRNA and protein than the other two types of receptors (DOR and KOR). Immunocytochemistry revealed that MOR, DOR and KOR receptors were predominantly present on the surface of cell membranes, although these receptors were also occasionally present in the cell cytoplasm.
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22
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Choe CY, Dong J, Law PY, Loh HH. Differential gene expression activity among species-specific polypyrimidine/polypurine motifs in mu opioid receptor gene promoters. Gene 2011; 471:27-36. [PMID: 20946943 PMCID: PMC3009460 DOI: 10.1016/j.gene.2010.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 10/04/2010] [Accepted: 10/05/2010] [Indexed: 02/07/2023]
Abstract
The mu opioid receptor (MOR) is the principle molecular target of opioid analgesics. An appropriate understanding of MOR gene expression across species is critical for understanding its analgesic functions in humans. Here, we undertake a cross-species analysis of the polymorphic polypyrimidine/polypurine (PPy/u) motif, a key enhancer of MOR gene expression. The mouse PPy/u motif is highly homologous to those of rat (67%) and human (83%), but drives reporter gene expression tenfold and fivefold more effectively than those of rat and human, respectively. Circular dichroism profiles of PPy/u oligonucleotides from different species showed that they are primarily different in structure. Conformational studies of reporter plasmids using confocal Raman spectra, S1 nuclease and restriction enzymes demonstrated that the structural difference is the result of changes in the phosphodiester backbone. Furthermore, these conformational disparities produce differences in torsional stress, as shown by topoisomerase II relaxation and activation of different levels of gene expression under hypertonic conditions. This study demonstrates that homologous PPy/u motifs adopt unique species-specific conformations with different mechanisms and activities for gene expression. We further discuss how structural aspects of transcription regulatory elements, rather than the sequence itself, are significant when studying functional gene expression regulatory elements.
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Affiliation(s)
- Chung-Youl Choe
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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Yu HY, Mu DG, Chen J, Yin W. Suppressive Effects of Intrathecal Paeoniflorin on Bee Venom-Induced Pain-Related Behaviors and Spinal Neuronal Activation. Pharmacology 2011; 88:159-66. [DOI: 10.1159/000330456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 06/21/2011] [Indexed: 11/19/2022]
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Kumar K, Kumar S, Kurupati RK, Seth MK, Mohan A, Hussain ME, Pasha S. Intracellular cAMP assay and Eu-GTP-γS binding studies of chimeric opioid peptide YFa. Eur J Pharmacol 2010; 650:28-33. [PMID: 20887721 DOI: 10.1016/j.ejphar.2010.09.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 07/26/2010] [Accepted: 09/14/2010] [Indexed: 11/20/2022]
Abstract
In our previous studies chimeric peptide of Met-enkephalin and FMRFa, YGGFMKKKFMRFamide (YFa), demonstrated concentration dependent κ- and μ-opioid receptor mediated antinociception without tolerance development. To gain further insight of the observed behavior of YFa, the present study was undertaken. The effect of chimeric peptide on forskolin-stimulated cAMP formation under acute and chronic treatment and stimulation of Eu-GTP-γS binding in CHO cells stably expressing κ- and μ-opioid receptors was assessed. YFa showed concentration dependent inhibition of forskolin-stimulated cAMP in both hKOR and hMOR-CHO cells; however, the inhibition at 1nM was significantly higher in hKOR cells and comparable to DynA (1-13) than that shown at 20nM in hMOR cells. Chronic treatment of YFa, similar to DynA (1-13), did not show significant change in forskolin-stimulated cAMP level in both hKOR and hMOR cells. However, chronic treatment of morphine and DAMGO showed an increase in forskolin-stimulated cAMP level in hMOR-CHO cells indicating superactivation of adenylyl cyclase. Eu-GTP-γS binding studies of YFa showed a concentration dependent adherent binding with κ- and μ-opioid receptors; however, the latter demonstrated significant binding at higher concentration. Thus the study indicates the chimeric opioid peptide YFa as a potent κ- receptor specific antinociceptive moiety, showing no tolerance and hence may serve as a lead in understanding the mechanism of tolerance development, antinociception and its modulation.
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Affiliation(s)
- Krishan Kumar
- Institute of Genomics and Integrative Biology (CSIR), Mall Road, Delhi, India
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25
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Kazi JA, Abu-Hassan MI. Gabapentin Completely Attenuated the Acute Morphine-Induced c-Fos Expression in the Rat Nucleus Accumbens. J Mol Neurosci 2010; 45:101-9. [DOI: 10.1007/s12031-010-9435-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 08/02/2010] [Indexed: 01/19/2023]
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Abstract
The proteins that mediate the analgesic and other effects of opioid drugs and endogenous opioid peptides are known as opioid receptors. Opioid receptors consist of a family of four closely-related proteins belonging to the large superfamily of G-protein coupled receptors. The three types of opioid receptors shown unequivocally to mediate analgesia in animal models are the mu (MOR), delta (DOR), and kappa (KOR) opioid receptor proteins. The role of the fourth member of the opioid receptor family, the nociceptin or orphanin FQ receptor (ORL), is not as clear as hyperalgesia, analgesia, and no effect was reported after administration of ORL agonists. There are now cDNA sequences for all four types of opioid receptors that are expressed in the brain of six species from three different classes of vertebrates. This review presents a comparative analysis of vertebrate opioid receptors using bioinformatics and data from recent human genome studies. Results indicate that opioid receptors arose by gene duplication, that there is a vector of opioid receptor divergence, and that MOR shows evidence of rapid evolution.
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Affiliation(s)
- Craig W Stevens
- Department of Pharmacology and Physiology, Oklahoma State University-Center for Health Sciences, Tulsa, OK, USA.
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27
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Deo SH, Barlow MA, Gonzalez L, Yoshishige D, Caffrey JL. Repeated arterial occlusion, delta-opioid receptor (DOR) plasticity and vagal transmission within the sinoatrial node of the anesthetized dog. Exp Biol Med (Maywood) 2008; 234:84-94. [PMID: 18997098 DOI: 10.3181/0808-rm-242] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Brief interruptions in coronary blood flow precondition the heart, engage delta-opioid receptor (DOR) mechanisms and reduce the damage that typically accompanies subsequent longer coronary occlusions. Repeated short occlusions of the sinoatrial (SA) node artery progressively raised nodal methionine-enkephalin-arginine-phenylalanine (MEAP) and improved vagal transmission during subsequent long occlusions in anesthetized dogs. The DOR type-1 (DOR-1) antagonist, BNTX reversed the vagotonic effect. Higher doses of enkephalin interrupted vagal transmission through a DOR-2 mechanism. The current study tested whether the preconditioning (PC) protocol, the later occlusion or a combination of both was required for the vagotonic effect. The study also tested whether evolving vagotonic effects included withdrawal of competing DOR-2 vagolytic influences. Vagal transmission progressively improved during successive SA nodal artery occlusions. The vagotonic effect was absent in sham animals and after DOR-1 blockade. After completing the PC protocol, exogenously applied vagolytic doses of MEAP reduced vagal transmission under both normal and occluded conditions. The magnitude of these DOR-2 vagolytic effects was small compared to controls and repeated MEAP challenges rapidly eroded vagolytic responses further. Prior DOR-1 blockade did not alter the PC mediated, progressive loss of DOR-2 vagolytic responses. In conclusion, DOR-1 vagotonic responses evolved from signals earlier in the PC protocol and erosion of competing DOR-2 vagolytic responses may have contributed to an unmasking of vagotonic responses. The data support the hypothesis that PC and DOR-2 stimulation promote DOR trafficking, and down regulation of the vagolytic DOR-2 phenotype in favor of the vagotonic DOR-1 phenotype. DOR-1 blockade may accelerate the process by sequestering newly emerging receptors.
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Affiliation(s)
- Shekhar H Deo
- University of North Texas Health Science Center, Department of Integrative Physiology, Cardiovascular Research Institute, Fort Worth, TX 76107, USA
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28
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Abstract
The mechanisms underlying responses to drugs of abuse have been widely investigated; however, less is known about pathways normally protective against the development of drug reinforcement. These pathways are also important since they may regulate individual differences in vulnerability to addiction. The neuropeptide galanin and its binding sites are expressed in brain areas important for drug reward. Previous studies have shown that centrally infused galanin attenuates morphine place preference and peripheral injection of galnon, a galanin agonist, decreases opiate withdrawal signs. The current studies in galanin knockout (GKO) mice examined the hypothesis that galanin is an endogenous negative regulator of opiate reward and identified downstream signaling pathways regulated by galanin. We show that GKO mice demonstrate increased locomotor activation following morphine administration, which is inhibited by acute administration of galnon. GKO mice also show enhanced morphine place preference, supporting the idea that galanin normally antagonizes opiate reward. In addition, morphine-induced ERK1/2 phosphorylation was increased in the VTA of both wild-type and GKO mice, but only the GKO mice showed increases in ERK1/2 and CREB phosphorylation in the amygdala or nucleus accumbens. Furthermore, a single systemic injection of galnon in GKO mice was sufficient to reverse some of the biochemical changes brought about by morphine administration. These data suggest that galanin normally attenuates behavioral and neurochemical effects of opiates; thus, galanin agonists may represent a new class of therapeutic targets for opiate addiction.
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29
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Wan Q, Wang X, Wang YJ, Song L, Wang SH, Ho WZ. Morphine suppresses intracellular interferon-alpha expression in neuronal cells. J Neuroimmunol 2008; 199:1-9. [PMID: 18562017 DOI: 10.1016/j.jneuroim.2008.04.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 04/09/2008] [Accepted: 04/14/2008] [Indexed: 11/30/2022]
Abstract
Interferon alpha (IFN-alpha) not only plays a key role in innate host immunity against infections but also is involved in the cellular functions of the central nervous system (CNS). In this study, we examined the impact of morphine on IFN-alpha expression in human neuronal cells (NT2-N). Similar to human immune cells, NT2-N cells also expressed IFN-alpha at both mRNA and protein levels. IFN-alpha expression in NT2-N cells, however, was inhibited by morphine. Naltrexone antagonized the inhibitory effect of morphine on IFN-alpha expression in NT2-N cells. The specific mu opioid receptor antagonist, Cys2, Tyr3, Arg5, Pen7-amide (CTAP), also blocked the morphine action on intracellular IFN-alpha expression. Investigation of the mechanisms involved in the morphine action showed that although morphine had little effect on the expression of key IFN regulatory factors (IRFs), morphine inhibited IFN-alpha promoter activation and suppressed the expression and phosphorylation of signal transducer and activator of transcription 1 (STAT1) in the neuronal cells. These findings provide direct in vitro evidence that opioids may impair neuronal cell-mediated innate protection in the CNS.
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Affiliation(s)
- Qi Wan
- Division of Allergy and Immunology, Joseph Stokes, Jr. Research Institute at The Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, United States
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30
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Yu HY, Liu MG, Liu DN, Shang GW, Wang Y, Qi C, Zhang KP, Song ZJ, Chen J. Antinociceptive effects of systemic paeoniflorin on bee venom-induced various ‘phenotypes’ of nociception and hypersensitivity. Pharmacol Biochem Behav 2007; 88:131-40. [PMID: 17854874 DOI: 10.1016/j.pbb.2007.07.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 07/05/2007] [Accepted: 07/16/2007] [Indexed: 10/23/2022]
Abstract
Paeoniflorin (PF), one of the active chemical compounds identified from the root of Paeonia lactiflora Pall, has been well-established to exhibit various neuroprotective actions in the central nervous system (CNS) after long-term daily administration. In the present study, by using the bee venom (BV) model of nociception and hypersensitivity, antinociceptive effects of PF were evaluated by intraperitoneal administration in conscious rats. When compared with saline control, systemic pre- and post-treatment with PF resulted in an apparent antinociception against both persistent spontaneous nociception and primary heat hypersensitivity, while for the primary mechanical hypersensitivity only pre-treatment was effective. Moreover, pre- and early post-treatment with PF (5 min after BV injection) could successfully suppress the occurrence and maintenance of the mirror-image heat hypersensitivity, whereas late post-treatment (3 h after BV) did not exert any significant impact. In the Rota-Rod treadmill test, PF administration did not affect the motor coordinating performance of rats. Furthermore, systemic PF application produced no significant influence upon BV-induced paw edema and swelling. Finally, the PF-produced antinociception was likely to be mediated by endogenous opioid receptors because of its naloxone-reversibility. Taken together, these results provide a new line of evidence showing that PF, besides its well-established neuroprotective actions in the CNS, is also able to produce analgesia against various 'phenotypes' of nociception and hypersensitivity via opioid receptor mediation.
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Affiliation(s)
- Hou-You Yu
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, PR China
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31
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Korzh A, Keren O, Gafni M, Bar-Josef H, Sarne Y. Modulation of extracellular signal-regulated kinase (ERK) by opioid and cannabinoid receptors that are expressed in the same cell. Brain Res 2007; 1189:23-32. [PMID: 18068691 DOI: 10.1016/j.brainres.2007.10.070] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 09/17/2007] [Accepted: 10/28/2007] [Indexed: 11/30/2022]
Abstract
In the present study we investigated the signal transduction pathways leading to the activation of extracellular signal-regulated kinase (ERK) by opioid or cannabinoid drugs, when their receptors are coexpressed in the same cell-type. In N18TG2 neuroblastoma cells, the opioid agonist etorphine and the cannabinoid agonist CP-55940 induced the phosphorylation of ERK by a similar mechanism that involved activation of delta-opioid receptors or CB1 cannabinoid receptors coupled to Gi/Go proteins, matrix metalloproteases, vascular endothelial growth factor (VEGF) receptors and MAPK/ERK kinase (MEK). In HEK-293 cells, these two drugs induced the phosphorylation of ERK by separate mechanisms. While CP-55940 activated ERK by transactivation of VEGFRs, similar to its effect in N18TG2 cells, the opioid agonist etorphine activated ERK by a mechanism that did not involve transactivation of a receptor tyrosine kinase. Interestingly, the activation of ERK by etorphine was resistant to the inhibition of MEK, suggesting the possible existence of a novel, undescribed yet mechanism for the activation of ERK by opioids. This mechanism was found to be specific to etorphine, as activation of ERK by the micro-opioid receptor (MOR) agonist DAMGO ([D-Ala(2), N-Me-Phe(4), Gly(5)-ol] enkephalin) was mediated by MEK in these cells, suggesting that etorphine and DAMGO activate distinct, ligand-specific, conformations of MOR. The characterization of cannabinoid- and opioid-induced ERK activation in these two cell-lines enables future studies into possible interactions between these two groups of drugs at the level of MAPK signaling.
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Affiliation(s)
- Alexander Korzh
- The Mauerberger Chair in Neuropharmacology, Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
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32
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Raut A, Rao VR, Ratka A. Changes in opioid receptor proteins during mitochondrial impairment in differentiated SK-N-SH cells. Neurosci Lett 2007; 422:187-92. [PMID: 17611027 PMCID: PMC2112745 DOI: 10.1016/j.neulet.2007.06.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 05/31/2007] [Accepted: 06/11/2007] [Indexed: 11/20/2022]
Abstract
Aging and neurodegenerative diseases are associated with oxidative damage that may contribute to changes in neurosensory processing, including pain. The effects of neuronal oxidation on the opioid receptor system are poorly understood. Earlier, we have reported that 3-nitroproprionic acid (3-NPA)-induced oxidative stress and impairment of mitochondrial energy metabolism significantly reduced the function of mu but not delta opioid receptors [A. Raut, M. Iglewski, A. Ratka, Differential effects of impaired mitochondrial energy production on the function of mu and delta opioid receptors in neuronal SK-N-SH cells, Neurosci. Lett. 404 (2006) 242-246]. In the present study, we studied the effects of 3-NPA-induced oxidative stress on protein levels of the mu, delta, and kappa opioid receptors (MOR, DOR, and KOR, respectively). The opioid-responsive differentiated SK-N-SH neuronal cells were used as an in vitro model. Cells were exposed to 0, 5, 10, and 20mM of 3-NPA for 0, 1, 2, 12, and 24h. After the 3-NPA treatments, plasma membrane preparations were made and used for the Western blot assay. There was a significant reduction in the level of the MOR protein while levels of DOR and KOR proteins remained unaffected after exposure to 3-NPA. These findings demonstrate for the first time that there is a selective impairment of the MOR protein under conditions of mitochondrial oxidative damage at the neuronal level. The reduction in the level of the MOR protein may contribute to the impairment of MOR function under oxidative damage conditions shown in our previous study.
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Affiliation(s)
- Atul Raut
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA
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33
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Tien LT, Ma T, Fan LW, Loh HH, Ho IK. Autoradiographic analysis of GABAA receptors in mu-opioid receptor knockout mice. Neurochem Res 2007; 32:1891-7. [PMID: 17562169 DOI: 10.1007/s11064-007-9373-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
Anatomical evidence indicates that gamma-aminobutyric acid (GABA)-ergic and opioidergic systems are closely linked and act on the same neurons. However, the regulatory mechanisms between GABAergic and opioidergic system have not been well characterized. In the present study, we investigated whether there are changes in GABA(A) receptors in mice lacking mu-opioid receptor gene. The GABA(A) receptor binding was carried out by autoradiography using [(3)H]-muscimol (GABA(A)), [(3)H]-flunitrazepam (FNZ, native type 1 benzodiazepine) and [(35)S]-t-butylbicyclophosphorothionate (TBPS, binding to GABA(A)-gated chloride channels) in brain slices of wild type and mu-opioid receptor knockout mice. The binding of [(3)H]-FNZ in mu-opioid receptor knockout mice was significantly higher than that of the wild type controls in most of the cortex and hippocampal CA1 and CA2 formations. mu-Opioid receptor knockout mice show significantly lower binding of [(35)S]-TBPS than that of the wild type mice in few of the cortical areas including ectorhinal cortex layers I, III, and V, but not in the hippocampus. There was no significant difference in binding of [(3)H]-muscimol between mu-opioid receptor knockout and wild type mice in the cortex and hippocampus. These data indicate that there are specific regional changes in GABA(A) receptor binding sites in mu-opioid receptor knockout mice. These data also suggest that there are compensatory up-regulation of benzodiazepine binding site of GABA(A) receptors in the cortex and hippocampus and down-regulation of GABA-gated chloride channel binding site of GABA(A) receptors in the cortex of the mu-opioid receptor knockout mice.
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Affiliation(s)
- Lu-Tai Tien
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA.
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34
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Song KY, Hwang CK, Kim CS, Choi HS, Law PY, Wei LN, Loh HH. Translational repression of mouse mu opioid receptor expression via leaky scanning. Nucleic Acids Res 2007; 35:1501-13. [PMID: 17284463 PMCID: PMC1865057 DOI: 10.1093/nar/gkm034] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 12/10/2006] [Accepted: 01/07/2007] [Indexed: 11/21/2022] Open
Abstract
Mu opioid receptor (MOR) expression is under temporal and spatial controls, but expression levels of the MOR gene are relatively low in vivo. In addition to transcriptional regulations, upstream AUGs (uAUGs) and open reading frames (uORFs) profoundly affect the translation of the primary ORF and thus the protein levels in several genes. The 5'-untranslated region (UTR) of mouse MOR mRNA contains three uORFs preceding the MOR main initiation codon. In MOR-fused EGFP or MOR promoter/luciferase reporter constructs, mutating each uAUG individually or in combinations increased MOR transient heterologous expression in neuroblastoma NMB and HEK293 cells significantly. Translation of such constructs increased up to 3-fold without altering the mRNA levels if either the third uAUG or both the second and third AUGs were mutated. Additionally, these uAUG-mediated translational inhibitions were independent of their peptide as confirmed by internal mutation analyses in each uORF. Translational studies indicated that protein syntheses were initiated at these uAUG initiation sites, with the third uAUG initiating the highest translation level. These results support the hypothesis that uORFs in mouse MOR mRNA act as negative regulators through a ribosome leaky scanning mechanism. Such leaky scanning resulted in the suppression of mouse MOR under normal conditions.
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Affiliation(s)
- Kyu Young Song
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
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35
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Deo SH, Johnson-Davis S, Barlow MA, Yoshishige D, Caffrey JL. Repeated δ1-opioid receptor stimulation reduces δ2-opioid receptor responses in the SA node. Am J Physiol Heart Circ Physiol 2006; 291:H2246-54. [PMID: 16782849 DOI: 10.1152/ajpheart.00122.2006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ultra-low-dose methionine-enkephalin-arginine-phenylalanine improves vagal transmission (vagotonic) and decreases heart rate via δ1-opioid receptors within the sinoatrial (SA) node. Higher doses activate δ2-opioid receptors, interrupt vagal transmission (vagolytic), and reduce the bradycardia. Preconditioning-like occlusion of the nodal artery produced a vagotonic response that was reversed by the δ1-antagonist 7-benzylidenaltrexone (BNTX). The following study tested the hypothesis that extended δ1-opioid receptor stimulation reduces subsequent δ2-receptor responses. The δ2-agonist deltorphin II was introduced in the SA node by microdialysis to evaluate δ2 responses before and after infusion of the δ1-agonist TAN-67. TAN-67 reduced the vagolytic effect of deltorphin by two-thirds. When the δ1-antagonist BNTX was combined with TAN-67, the deltorphin response was preserved, suggesting that attrition of the prior response was mediated by δ1 activity. When TAN-67 was omitted in time control studies, some loss of δ2 responses was apparent in the absence of the δ1 treatment. This loss was also eliminated by BNTX, suggesting that the attenuation of the response after deltorphin alone was also the result of δ1 activity. Additional studies tested TAN-67 alone in the absence of prior deltorphin. When time controls were conducted without the initial deltorphin treatment, a robust vagolytic response was observed. When TAN-67 preceded the delayed deltorphin, the vagolytic response was eroded, indicating an independent effect of TAN-67. BNTX infused afterward was unable to restore the δ2 response. These data support the conclusion that the loss of the δ2 response resulted from reduced δ2 activity mediated by continued δ1-receptor stimulation and not the arithmetic consequence of increased competition from that same δ1 receptor.
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MESH Headings
- Analgesics/pharmacology
- Analgesics, Opioid/pharmacology
- Animals
- Benzylidene Compounds/pharmacology
- Bradycardia/drug therapy
- Bradycardia/physiopathology
- Dogs
- Dose-Response Relationship, Drug
- Enkephalin, Methionine/analogs & derivatives
- Enkephalin, Methionine/pharmacology
- Female
- Male
- Microdialysis
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Narcotic Antagonists/pharmacology
- Oligopeptides/pharmacology
- Quinolines/pharmacology
- Receptors, Opioid, delta/classification
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/metabolism
- Sinoatrial Node/drug effects
- Sinoatrial Node/innervation
- Sinoatrial Node/physiology
- Stimulation, Chemical
- Vagus Nerve/drug effects
- Vagus Nerve/physiology
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Affiliation(s)
- S H Deo
- Dept. of Integrative Physiology, Univ. of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth TX 76107, USA.
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36
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Raut A, Iglewski M, Ratka A. Differential effects of impaired mitochondrial energy production on the function of mu and delta opioid receptors in neuronal SK-N-SH cells. Neurosci Lett 2006; 404:242-6. [PMID: 16808998 DOI: 10.1016/j.neulet.2006.05.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 05/17/2006] [Accepted: 05/31/2006] [Indexed: 10/24/2022]
Abstract
Oxidative stress contributes to changes in neurosensory processing, including pain, that occur during aging and neurodegeneration. The effects of neuronal oxidation on the opioid system are poorly understood. In this in vitro study, oxidative stress was induced by 3-nitroproprionic acid (3-NPA) in opioid-responsive differentiated SK-N-SH cells. Changes in the inhibitory effects of opioid receptor agonists on intracellular cAMP were used as a marker of the function of mu and delta opioid receptors (MOR and DOR, respectively). Cells were treated with morphine and selective MOR and DOR agonists and antagonists to characterize the function of each receptor subtype. Cyclic AMP (cAMP) was measured by enzyme immunoassay. Levels of reactive oxygen species (ROS) were assessed using the 2',7'-dichlorofluorescin diacetate assay. Exposure of cells to 3-NPA resulted in an increase in ROS. After 3-NPA exposure, there was a significant attenuation of the inhibitory effect of morphine and DAMGO but not of DPDPE on cAMP. In cells pretreated with CTOP, 3-NPA did not change the inhibitory effect on cAMP. These findings demonstrate for the first time that under conditions of mitochondrial damage, the function of MOR is significantly decreased, while the function of DOR does not change, suggesting that the effect of 3-NPA on opioid receptors is subtype-specific.
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MESH Headings
- Cell Line, Tumor
- Energy Metabolism/physiology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Humans
- Mitochondria/metabolism
- Neuroblastoma
- Neurons/physiology
- Nitro Compounds/pharmacology
- Propionates/pharmacology
- Reactive Oxygen Species/metabolism
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/physiology
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Affiliation(s)
- Atul Raut
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, 76107, USA
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37
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Finnegan TF, Chen SR, Pan HL. Mu opioid receptor activation inhibits GABAergic inputs to basolateral amygdala neurons through Kv1.1/1.2 channels. J Neurophysiol 2005; 95:2032-41. [PMID: 16306173 DOI: 10.1152/jn.01004.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The basolateral amygdala (BLA) is the major amygdaloid nucleus distributed with mu opioid receptors. The afferent input from the BLA to the central nucleus of the amygdala (CeA) is considered important for opioid analgesia. However, little is known about the effect of mu opioids on synaptic transmission in the BLA. In this study, we examined the effect of mu opioid receptor stimulation on the inhibitory and excitatory synaptic inputs to CeA-projecting BLA neurons. BLA neurons were retrogradely labeled with a fluorescent tracer injected into the CeA of rats. Whole cell voltage-clamp recordings were performed on labeled BLA neurons in brain slices. The specific mu opioid receptor agonist, (D-Ala2,N-Me-Phe4,Gly5-ol)-enkephalin (DAMGO, 1 microM), significantly reduced the frequency of miniature inhibitory postsynaptic currents (mIPSCs) in 77% of cells tested. DAMGO also significantly decreased the peak amplitude of evoked IPSCs in 75% of cells examined. However, DAMGO did not significantly alter the frequency of mEPSCs or the peak amplitude of evoked EPSCs in 90% and 75% of labeled cells, respectively. Bath application of the Kv channel blockers, 4-AP (Kv1.1, 1.2, 1.3, 1.5, 1.6, 3.1, 3.2), alpha-dendrotoxin (Kv1.1, 1.2, 1.6), dendrotoxin-K (Kv1.1), or tityustoxin-Kalpha (Kv1.2) each blocked the inhibitory effect of DAMGO on mIPSCs. Double immunofluorescence labeling showed that some of the immunoreactivities of Kv1.1 and Kv1.2 were colocalized with synaptophysin in the BLA. This study provides new information that activation of presynaptic mu opioid receptors primarily attenuates GABAergic synaptic inputs to CeA-projecting neurons in the BLA through a signaling mechanism involving Kv1.1 and Kv1.2 channels.
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MESH Headings
- Amygdala/chemistry
- Amygdala/physiology
- Analgesics, Opioid/pharmacology
- Animals
- Bicuculline/pharmacology
- Elapid Venoms/pharmacology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Excitatory Postsynaptic Potentials/physiology
- Kv1.1 Potassium Channel/analysis
- Kv1.1 Potassium Channel/drug effects
- Kv1.1 Potassium Channel/physiology
- Kv1.2 Potassium Channel/analysis
- Kv1.2 Potassium Channel/drug effects
- Kv1.2 Potassium Channel/physiology
- Limbic System/physiology
- Male
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Patch-Clamp Techniques
- Peptides/pharmacology
- Potassium Channel Blockers/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid/physiology
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/physiology
- Scorpion Venoms/pharmacology
- Signal Transduction/physiology
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- Synaptophysin/analysis
- gamma-Aminobutyric Acid/physiology
- Nociceptin Receptor
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Affiliation(s)
- Thomas F Finnegan
- Department of Anesthesiology , Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey Pennsylvania, USA
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38
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Freye E, Levy J. Constitutive opioid receptor activation: a prerequisite mechanism involved in acute opioid withdrawal. Addict Biol 2005; 10:131-7. [PMID: 16191664 DOI: 10.1080/13556210500123019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The opioid receptor antagonist naltrexone, which is used in detoxification and rehabilitation programmes in opioid addicts, can precipitate opioid withdrawal symptoms even in patients who have no opioid present. We tested the hypothesis that in order to precipitate withdrawal, opioids need to convert the inactive opioid receptor site via protein kinase C into a constitutively active form on which the antagonist precipitates withdrawal. Acute microg/kg), given for 6 days, which was followed by the antagonist naltrexone (20 microg/kg i.v.) in the awake trained canine (n = 10). Abrupt displacement of opioid binding resulted in acute withdrawal symptoms: increase in blood pressure, heart rate, increase in amplitude height of somatosensory evoked potential, reduced tolerance to colon distention and a significant increase in grading of vegetative variables (restlessness, panting, thrashing of the head, whining, yawning, gnawing, salivation and/or rhinorrhoea, mydriasis, stepping of extremities and vomiting). Following a washout period of 14 days, the same animals were given the highly specific protein kinase C inhibitor H7 (250 microg/kg) prior to the same dosages of sufentanil and naltrexone. Such pretreatment was able to either attenuate or completely abolish the acute withdrawal symptoms. The data suggest that for precipitation of withdrawal, intracellular phosphorylation is a prerequisite in order to activate the opioid mu-receptor. In such a setting, naltrexone acts like an 'inverse agonist' relative to the action of the antagonist on a non-preoccupied receptor site not being exposed previously to a potent opioid agonist.
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Affiliation(s)
- E Freye
- Clinics of Vascular Surgery and Renal Transplantation, University Clinics of Düsseldorf, Moorenstrasse, Düsseldorf, Germany.
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39
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Abstract
Opioid receptors belong to the large superfamily of seven transmembrane-spanning (7TM) G protein-coupled receptors (GPCRs). As a class, GPCRs are of fundamental physiological importance mediating the actions of the majority of known neurotransmitters and hormones. Opioid receptors are particularly intriguing members of this receptor family. They are activated both by endogenously produced opioid peptides and by exogenously administered opiate compounds, some of which are not only among the most effective analgesics known but also highly addictive drugs of abuse. A fundamental question in addiction biology is why exogenous opioid drugs, such as morphine and heroin, have a high liability for inducing tolerance, dependence, and addiction. This review focuses on many aspects of opioid receptors with the aim of gaining a greater insight into mechanisms of opioid tolerance and dependence.
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Affiliation(s)
- Maria Waldhoer
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, Emeryville, California 94608, USA.
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40
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Kim CS, Hwang CK, Choi HS, Song KY, Law PY, Wei LN, Loh HH. Neuron-restrictive silencer factor (NRSF) functions as a repressor in neuronal cells to regulate the mu opioid receptor gene. J Biol Chem 2004; 279:46464-73. [PMID: 15322094 DOI: 10.1074/jbc.m403633200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mu opioid receptor (MOR) is expressed in the central nervous system and specific cell lines with varying expression levels perhaps playing important roles. One of the neuronal-specific transcription regulators, neuron-restrictive silencer factor (NRSF), has been shown to repress the expression of neuron-specific genes in non-neuronal cells. However, we showed here that the neuron-restrictive silencer element (NRSE) of MOR functions as a critical regulator to repress the MOR gene expression in specific neuronal cells depending on NRSF expression level. Using co-transfection studies, we showed that the NRSE of the MOR promoter is functional in NRSF-positive cells (NS20Y and HeLa) but not in NRSF-negative cells (PC12). NRSF binds to the NRSE of the MOR gene in a sequence-specific manner confirmed by supershift and chromatin immunoprecipitation assays, respectively. The suppression of NRSF activity with either trichostatin A or a dominant-negative NRSF induced MOR promoter activity and transcription of the MOR gene. When the NRSF was disrupted in NS20Y and HeLa cells using small interfering RNA, the transcription of the endogenous target MOR gene increased significantly. This provides direct evidence the role of NRSF in the cells and also indicates that NRSF expression is regulated by post-translational modification in neuronal NMB cells. Our data suggested that NRSF can function as a repressor of MOR transcription in specific cells, via a mechanism dependent on the MOR NRSE.
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Affiliation(s)
- Chun Sung Kim
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
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41
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Suzuki T, Izumimoto N, Takezawa Y, Fujimura M, Togashi Y, Nagase H, Tanaka T, Endoh T. Effect of repeated administration of TRK-820, a κ-opioid receptor agonist, on tolerance to its antinociceptive and sedative actions. Brain Res 2004; 995:167-75. [PMID: 14672806 DOI: 10.1016/j.brainres.2003.09.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Repeated administration of micro-opioid receptor agonist, morphine induces tolerance not only to the antinociceptive effect but also to other pharmacological effects, resulting in shortened working duration and decreased efficacy. But less is known about kappa-opioid agonist-induced tolerance. The tolerance-development potency of kappa-opioid receptor agonists with a focus on TRK-820 was characterized. After five administrations of kappa-opioid receptor agonists, TRK-820 (0.1-0.8 mg/kg), U-50,488H (10-80 mg/kg) and ICI-199,441 (0.025-0.2 mg/kg) subcutaneously over 3 days, tolerance to the antinociceptive effects, assessed by an acetic acid-induced abdominal constriction test, developed in a repeated dose-dependent manner. The tolerance-development potency of TRK-820 was the least among these kappa-opioid receptor agonists. Similarly, TRK-820 and U-50,488H induced tolerance to their sedative effects as judged by a wheel-running test in mice. Greater tolerance was developed to the sedative effect than to the antinociceptive effect in both compounds. After repeated administration, the number of kappa-opioid receptors in the mouse brain was reduced by U-50,488H (80 mg/kg) but not by TRK-820 (0.4 mg/kg). There was no change of the affinity by the treatment with both compounds. These results demonstrated that the kappa-opioid receptor agonists developed tolerance both to the antinociceptive and the sedative effects, though the tolerance to the sedative effect developed more readily than tolerance to the antinociceptive effect. The difference in the potency for down-regulating the kappa-opioid receptors in the brain may account for the tolerance-development potency of the compounds.
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Affiliation(s)
- Tomohiko Suzuki
- Pharmaceutical Research Laboratories, Toray Industries, Inc., 1111, Tebiro Kamakura, Kanagawa, 248-8555 Japan.
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42
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Wang J, Barke RA, Charboneau R, Loh HH, Roy S. Morphine negatively regulates interferon-gamma promoter activity in activated murine T cells through two distinct cyclic AMP-dependent pathways. J Biol Chem 2003; 278:37622-31. [PMID: 12842891 DOI: 10.1074/jbc.m301224200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To explore the mechanism by which morphine promotes the incidence of HIV infection, we evaluated the regulatory role of morphine on the interferon-gamma (IFN-gamma) promoter in activated T cells from wild type and mu-opioid receptor knockout mice. Our results show that morphine inhibited anti-CD3/CD28-stimulated IFN-gamma promoter activity in a dose-dependent manner. Chronic morphine treatment of T cells increased intracellular cAMP. To evaluate the role of cAMP in morphine's modulatory function, the effects of dibutyryl cyclic AMP and forskolin were investigated. Both dibutyryl cyclic AMP and forskolin treatment inhibited IFN-gamma promoter activity. Treatment with pertussis toxin, but not with a protein kinase A inhibitor, antagonized morphine's inhibitory effects. Morphine inhibited phosphorylation of ERK1/2 and p38 MAPK; in addition, morphine treatment in the presence of either ERK1/2 or p38 MAPK inhibitor (PD98059 or SB203580) resulted in an additive inhibition of IFN-gamma promoter activity. The transcription factor activator protein-1, NF-kappaB, and nuclear factor of activated T cells (NFAT) were negatively regulated by morphine. Overexpression of NF-kappaB p65 rescued the inhibitory effect of morphine on IFN-gamma promoter activity. However, only when NFATc1 was co-overexpressed with c-fos was the inhibitory effect of morphine on IFN-gamma promoter counteracted. The inhibitory effects of morphine were not observed in T cells obtained from mu-opioid receptor knockout mice, suggesting that morphine modulation of IFN-gamma promoter activity is mediated through the mu-opioid receptor. In summary, our data indicate that morphine modulation of IFN-gamma promoter activity is mediated through two distinct cAMP-dependent pathways, the NF-kappaB signaling pathway and the ERK1/2, p38 MAPK, AP-1/NFAT pathway.
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Affiliation(s)
- Jinghua Wang
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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43
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Yu X, Mao X, Blake AD, Li WX, Chang SL. Morphine and endomorphins differentially regulate micro-opioid receptor mRNA in SHSY-5Y human neuroblastoma cells. J Pharmacol Exp Ther 2003; 306:447-54. [PMID: 12754318 DOI: 10.1124/jpet.103.048694] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A sensitive quantitative-competitive reverse transcriptase-polymerase chain reaction method was developed to measure micro-opioid receptor (MOR) mRNA expression in SHSY-5Y neuroblastoma cells. Differentiation of SHSY-5Y cells with either retinoic acid (RA) or 12-o-tetradecanoyl-phorbol-13-acetate (TPA) significantly increased MOR mRNA levels. Morphine treatment (10 microM) for 24 h decreased MOR mRNA levels in control, as well as RA- and TPA-differentiated cells. In contrast, chronic exposure to the opioid peptides endomorphin-1 or endomorphin-2 significantly increased MOR mRNA levels in undifferentiated and RA-differentiated cells. An opioid antagonist, naloxone, reversed the morphine and endomorphin-1 and -2 effects on MOR mRNA levels in undifferentiated SHSY-5Y cells, but naloxone had differential reversing effects on the agonists' regulation of MOR mRNA in RA- or TPA-differentiated cells. To investigate whether the changes in MOR mRNA expression paralleled changes in MOR receptor function, intracellular cAMP accumulation in SHSY-5Y cells was measured. After chronic treatment with morphine, forskolin-induced cAMP levels in SHSY-5Y cells were significantly higher than those of untreated control cells. In contrast, forskolin-induced cAMP accumulation levels were lower in cells treated with endomorphin-1 or -2 than in untreated control cells. Together, our studies indicate that the opioid alkaloid morphine and the opioid peptides endomorphin-1 and -2 differentially regulate MOR mRNA expression and MOR function in SHSY-5Y cells.
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Affiliation(s)
- Xin Yu
- Department of Biology, Seton Hall University, 400 South Orange Ave, South Orange, NJ 07079, USA
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44
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Tomassini N, Renaud FL, Roy S, Loh HH. Mu and delta receptors mediate morphine effects on phagocytosis by murine peritoneal macrophages. J Neuroimmunol 2003; 136:9-16. [PMID: 12620638 DOI: 10.1016/s0165-5728(02)00463-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Studies with selective opioid agonists show that mu- and delta(2)-opioid receptors, but not kappa, are involved in opioid inhibition of phagocytosis in elicited murine macrophages. All mu and delta(2) agonists tested had similar maximal effects on phagocytosis, and all dose-response curves suggest positive cooperativity. In addition, mu and delta antagonists antagonized the effect of both mu and delta agonists. Furthermore, in mu-opioid receptor knockout mice (MORKO), we observed a decrease in potency and maximal effect for a delta agonist. These data suggest that mu and delta receptors are not only involved in the modulation of phagocytosis in macrophages, but they also affect each other's activity by an unknown cooperative mechanism.
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MESH Headings
- Animals
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Female
- Macrophages/drug effects
- Macrophages/immunology
- Macrophages/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Morphine/pharmacology
- Narcotic Antagonists/pharmacology
- Peritoneum/cytology
- Peritoneum/drug effects
- Peritoneum/immunology
- Phagocytosis/drug effects
- Phagocytosis/immunology
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/deficiency
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Affiliation(s)
- Nilka Tomassini
- Biology Department, University of Puerto Rico, POB 23360 Río Piedras Campus, San Juan 00931-3360, Puerto Rico
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45
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Abstract
Recent discoveries in opioid pharmacology help explain the enormous variability in clinical responses to these powerful analgesics. Although there is only one m opioid receptor gene, splice variants of that gene's expression result in a panoply of different functioning receptors. Other sources of variable response include polymorphisms in the m opioid receptor regulatory region, and pharmacokinetic differences because of cytochrome P-450 mono-oxygenase heterogeneity. Analgesic tolerance is likely the key phenomenon limiting the benefit of opioids. A plethora of intracellular pathways affects this. Among them are the N-methyl-D-aspartate receptor, protein kinase C gamma activity, nitric oxide synthase, and GM1 ganglioside content of the neuronal membrane. Clinical studies undercut the routine use of meperidine in most settings. Other studies have shown better ways to diminish opioid side effects.
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MESH Headings
- Analgesics, Opioid/adverse effects
- Analgesics, Opioid/therapeutic use
- Animals
- Clinical Trials as Topic
- Drug Tolerance
- Humans
- Pain/drug therapy
- Pain/physiopathology
- Receptors, Opioid/drug effects
- Receptors, Opioid/genetics
- Receptors, Opioid/physiology
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/physiology
- Trans-Activators/genetics
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Affiliation(s)
- Eric Chevlen
- Cancer Care Center, St. Elizabeth Hospital, 1044 Belmont Avenue, Youngstown, OH 44501, USA.
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46
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Liu NJ, Gintzler AR. Facilitative interactions between vasoactive intestinal polypeptide and receptor type-selective opioids: implications for sensory afferent regulation of spinal opioid action. Brain Res 2003; 959:103-10. [PMID: 12480163 DOI: 10.1016/s0006-8993(02)03734-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Afferent tone is known to influence spinal opioid antinociception but the underlying neurochemical events are not well defined. This study investigates the consequence on cAMP formation of the coincident activation of signal transduction sequelae initiated by an afferent transmitter and opioid using dissociated spinal cord tissue. Afferent transmission was simulated via the addition of vasoactive intestinal polypeptide (VIP), a pelvic visceral afferent transmitter. Individually, mu, delta-, or kappa-selective opioids (1 microM each) did not alter basal spinal content of cAMP. However, VIP (1 microM) and the delta-opioid selective agonist, [D-Pen(2,5)] enkephalin (DPDPE; 1 microM), in combination, manifest a striking facilitative interaction to augment spinal levels of cAMP. Facilitative interactions between VIP and kappa- or mu-opioids were of a reduced magnitude or not observed, respectively. Blockade of delta-opioid or VIP receptors using naltrindole or VIP6-28, respectively antagonized the VIP-DPDPE facilitative interaction, as did pertussis toxin treatment. The VIP-DPDPE facilitative interaction was also eliminated by phospholipase Cbeta inhibition and inositol trisphosphate receptor blockade. This suggests that modulation of Ca(2+) trafficking by VIP and delta-opioid agonists is a point of convergence of their respective signal transduction cascades, the concomitant action at which achieves cytosolic Ca(2+) concentrations that are now sufficient for the activation of signaling molecules, e.g. Ca(2+)/calmodulin-stimulated adenylyl cyclase isoforms. These data underscore the plasticity of spinal delta-opioid neurochemical sequelae and their dependence on concomitant afferent transmitter-initiated neurochemical events.
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MESH Headings
- Afferent Pathways/drug effects
- Analgesics, Opioid/pharmacology
- Animals
- Cell Culture Techniques
- Cyclic AMP/analysis
- Cyclic AMP/metabolism
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Female
- Narcotics/pharmacology
- Neuronal Plasticity/physiology
- Neurotransmitter Agents/pharmacology
- Ovariectomy
- Rats
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Vasoactive Intestinal Peptide/antagonists & inhibitors
- Receptors, Vasoactive Intestinal Peptide/drug effects
- Receptors, Vasoactive Intestinal Peptide/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Spinal Cord/chemistry
- Spinal Cord/metabolism
- Vasoactive Intestinal Peptide/pharmacology
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Affiliation(s)
- Nai Jiang Liu
- Department of Biochemistry, State University of New York, Downstate Medical Center, Box 8, 450 Clarkson Ave., Brooklyn, NY 11203, USA
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47
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Abstract
This paper reviews the preclinical literature related to the effects of stress on neurobiological and neuroendocrine systems. Preclinical studies of stress provide a comprehensive model for understanding neurobiological alterations in post-traumatic stress disorder (PTSD). The pathophysiology of stress reflects long-standing changes in biological stress response systems and in systems involved in stress responsivity, learning, and memory. The neural circuitry involved includes systems mediating hypothalamic-pituitary-adrenal (HPA) axis, norepinephrine (locus coeruleus), and benzodiazepine, serotonergic, dopaminergic, neuropeptide, and central amino acid systems. These systems interact with brain structures involved in memory, including hippocampus, amygdala, and prefrontal cortex. Stress responses are of vital importance in living organisms; however excessive and/or repeated stress can lead to long-lasting alterations in these circuits and systems involved in stress responsiveness. Intensity and duration of the stressor, and timing of the stressor in life, have strong impact in this respect.
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Affiliation(s)
- Eric Vermetten
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 1639 Pierce Drive, Atlanta, GA 30322, USA.
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48
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Abstract
The major binding site for morphine is the mu opioid receptor (MOR), which mediates morphine's analgesic and euphoric effects. The MOR gene is highly regulated at the level of transcription. The present study examined DNA-protein interactions in the human MOR (hMOR) -500 to -292 promoter region, and tested whether chronic opioid drug treatment could modulate these DNA-protein interactions. 5'-deletion and transient transfection assays in SK-N-SH cells revealed four regions that activated hMOR gene transcription. A 60 bp sequence (-351 to -292) upstream of the proximal transcription initiation site (-252) contained cis-elements required for basal promoter activity. Sp1 and Sp3 bound to this 60 bp region, which was confirmed by electromobility shift assays using a Sp1 consensus oligo as competitor and specific antibodies against Sp1 and Sp3. Methylation interference analysis localized the Sp1 binding site to the sequence CCCTCCTCCC (-310 to -301) and also suggested that additional transcription factors, other than Sp1-related proteins, contacted the -321 to -301 sequence. Moreover, the binding of Sp1/Sp3 to the hMOR promoter was significantly enhanced by chronic exposure to [D-Ala(2), N-Me-Phe(4), Gly(5)-ol] enkephalin (DAMGO), a selective MOR agonist, and this effect was attenuated specifically by pretreatment with a MOR antagonist, naloxone. Taken together, the present studies demonstrated, for the first time, that the binding of Sp1/Sp3 to the hMOR proximal promoter could be modulated by chronic DAMGO treatment. Such enhanced binding of Sp1/Sp3 to the promoter may lead to a functional change in hMOR gene transcription.
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Affiliation(s)
- Y Xu
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 4602-5121, USA
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49
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Galeotti N, Ghelardini C, Bartolini A. Differential prevention of morphine amnesia by antisense oligodeoxynucleotides directed against various Gi-protein alpha subunits. Br J Pharmacol 2001; 133:267-74. [PMID: 11350863 PMCID: PMC1572787 DOI: 10.1038/sj.bjp.0704081] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The effect of the i.c.v. administration of pertussis toxin (PTX) and antisense oligodeoxynucleotide directed against the alpha subunit of different Gi-proteins (anti-Gialpha1, anti-Gialpha2, anti-Gialpha3) on amnesia induced by morphine was evaluated in the mouse passive avoidance test. The administration of morphine (6 - 10 mg kg(-1) i.p.) immediately after the training session produced amnesia that was prevented by PTX (0.25 microg per mouse i.c.v.) administered 7 days before the passive avoidance test. Anti-Gialpha1 (6.25 microg per mouse i.c.v.) and anti-Gialpha3 (12.5 microg per mouse i.c.v.), administered 18 and 24 h before the training session, prevented the morphine amnesia. By contrast, pretreatment with anti-Gialpha2 (3.12 - 25 microg per mouse i.c.v.) never modified the impairment of memory processes induced by morphine. At the highest effective doses, none of the compounds used impaired motor coordination, as revealed by the rota rod test, nor modified spontaneous motility and inspection activity, as revealed by the hole board test. These results suggest the important role played by Gi1 and Gi3 protein subtypes in the transduction mechanism involved in the impairment of memory processes produced by morphine.
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Affiliation(s)
- Nicoletta Galeotti
- Department of Preclinical and Clinical Pharmacology, Viale G. Pieraccini 6, I-50139 Florence, Italy
| | - Carla Ghelardini
- Department of Preclinical and Clinical Pharmacology, Viale G. Pieraccini 6, I-50139 Florence, Italy
- Author for correspondence:
| | - Alessandro Bartolini
- Department of Preclinical and Clinical Pharmacology, Viale G. Pieraccini 6, I-50139 Florence, Italy
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50
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Xu Y, Carr LG. Transcriptional regulation of the human mu opioid receptor (hMOR) gene: evidence of positive and negative cis-acting elements in the proximal promoter and presence of a distal promoter. DNA Cell Biol 2001; 20:391-402. [PMID: 11506703 DOI: 10.1089/104454901750361451] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The mu opioid receptor (MOR), the primary binding site for morphine, is an important target for treating pain and drug addiction. The MOR gene is tightly regulated at the level of transcription, and potential polymorphisms in its 5' regulatory region can cause individual variation in MOR gene expression, nociception, and opiate responses. To study the 5' regulatory region of the human MOR gene (hMOR), we further investigated our previous finding of two regulatory regions and have localized a 40-bp positive cis-acting element and a 35-bp negative cis-acting element that regulate hMOR transcription in SK-N-SH cells. Electromobility shift assays and methylation interference assay with the 40-bp probe suggested that protein contacts were made with the core recognition sequence GCC (-510 to -508). The 35-bp sequence (-694 to -660) was the hMOR homolog of the mMOR negative regulatory element, and it suppressed proximal promoter activity of the hMOR gene. Additionally, the presence of an hMOR distal promoter was confirmed using RT-PCR. However, the activity of the distal promoter construct (-2325 to -777) was weak compared with the activity of the proximal promoter construct (-776 to -212).
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Affiliation(s)
- Y Xu
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5121, USA
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