Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 7, 2016; 22(5): 1834-1843
Published online Feb 7, 2016. doi: 10.3748/wjg.v22.i5.1834
Electroacupuncture at ST25 inhibits jejunal motility: Role of sympathetic pathways and TRPV1
Zhi Yu, Na Zhang, Chun-Xia Lu, Ting-Ting Pang, Kai-Yue Wang, Jing-Feng Jiang, Bing Zhu, Bin Xu
Zhi Yu, Na Zhang, Chun-Xia Lu, Ting-Ting Pang, Kai-Yue Wang, Jing-Feng Jiang, Bin Xu, Key Laboratory of Integrated Acupuncture and Drugs, Nanjing University of Chinese Medicine, Nanjing 210023, Jiangsu Province, China
Bing Zhu, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
Author contributions: Yu Z and Zhang N contributed equally to this work; Xu B and Zhu B Conceived and designed the experiments; Yu Z and Zhang N performed the experiments and wrote the paper; Lu CX, Pang TT and Wang KY performed the experiments; Yu Z and Jiang JF analyzed the data; all authors read and approved the final version of the article to be published.
Supported by The National Key Basic Research Program (973 Program), No. 2011CB505206; the National Natural Science Foundation of China, No. 81202744, No. 81373749 and No. 81574071; and Jiangsu Provincial Qinglan Project Sci-tech Innovation Team.
Institutional review board statement: The study was reviewed and approved by Institutional Review Board of the Nanjing University of Chinese Medicine.
Institutional animal care and use committee statement: All experimental manipulations were undertaken in accordance with the Guide for the Care and Use of Laboratory Animals (National Institutes of Health), and the study was approved by the Institutional Animal Care and Use Committee of Nanjing University of Chinese Medicine.
Conflict-of-interest statement: The authors declare that there are no conflicts of interest to disclose.
Data sharing statement: No additional unpublished data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Bin Xu, PhD, Professor, Key Laboratory of Integrated Acupuncture and Drugs, Nanjing University of Chinese Medicine, No. 138 Xianlin Road, Nanjing 210023, Jiangsu Province, China. xuuuux@sina.com
Telephone: +86-25-86798095 Fax: +86-25-86798095
Received: May 10, 2015
Peer-review started: May 12, 2015
First decision: July 19, 2015
Revised: August 4, 2015
Accepted: November 9, 2015
Article in press: November 9, 2015
Published online: February 7, 2016
Processing time: 255 Days and 17.9 Hours
Abstract

AIM: To investigate whether electroacupuncture (EA) at ST25 affects jejunal motility in vivo and if so, whether a sympathetic pathway is involved.

METHODS: Jejunal motility was assessed using a manometric balloon placed in the jejunum approximately about 3-5 cm away from the suspensory ligament of the duodenum in anesthetized animals. The effects of EA at ST25 were measured in male Sprague-Dawley rats, some of which were treated with propranolol or clenbuterol (EA intensities: 1, 3, 5, 7, and 9 mA), and in male transient receptor potential vanilloid-1 (TRPV1) (capsaicin receptor) knockout mice (EA intensities: 1, 2, and 4 mA).

RESULTS: Anesthetized rats exhibited three types of fasting jejunal motor patterns (types A, B, and C), and only type C rats responded to EA stimulation. In type C rats, EA at ST25 significantly suppressed the motor activity of the jejunum in an intensity-dependent manner. The inhibitory effect of EA was weakened by propranolol (β adrenoceptor antagonist) and disappeared with clenbuterol (β adrenoceptor agonist) induced inhibition of motility, suggesting that the effect of EA on motility is mediated via a sympathetic pathway. Compared with wild-type mice, EA at ST25 was less effective in TRPV1 knockout mice, suggesting that this multi-modal sensor channel participates in the mechanism.

CONCLUSION: EA at ST25 was found to inhibit jejunal motility in an intensity-dependent manner, via a mechanism in which sympathetic nerves and TRPV1 receptors play an important role.

Keywords: Gastrointestinal disorder; Jejunal motility; Electroacupuncture; Sympathetic nervous system; Transient receptor potential vanilloid-1

Core tip: Evidence from clinical studies has shown that acupuncture on the abdomen was effective for both diarrhea and abdominal pain, suggesting that acupuncture at this point may inhibit gastrointestinal motility. However, its mechanism has not been established. In this work, we concluded that abdominal electroacupuncture (EA) (at ST25) may alter jejunal motility via a somatosympathetic reflex, and that transient receptor potential vanilloid-1 may serve as an EA-responsive channel mediating this reflex.