Expression of the P2X2 receptor in different classes of ileum myenteric neurons in the female obese ob/ob mouse

Figure 1 Immunoreactivity for P2X₂ receptor (A, D, G, J), nitric oxide synthase (B, E), choline acetyltransferase (H, K; merged images C, F, I, L) was examined in ileum myenteric plexus neurons from the control group (A-C, G-I) and the obese ob/ob group (D-F, J-L). Single arrows show double-labeled P2X₂ receptor (P2X₂R)- and nitric oxide synthase (NOS)-immunoreactivity neurons in the control group (CG) (A-C) and obese group (OG) (D-F) groups. Double-labeling for P2X₂R and choline acetyltransferase (ChAT) in CG neurons (G-I) and OG (J-L) is indicated by arrowheads.

Figure 2 Immunoreactivity for P2X₂ receptor (A, C, E, G) and calretinin (B, D, F, H) was examined in the ileum myenteric neurons of the control group (A, B, E, F) and the obese group (C, D, G, H). Single arrows show double labeling for P2X₂ receptor and calretinin (CalR) in the neurons of the control group (CG) (A, B) and the obese group (OG) (C, D). E, F: An example of a Dogiel type I neuron with many lamellar and short dendrites; G, H: A neuron with Dogiel type II morphology with a round and smooth cell body and lipofuscin evident in the cytoplasm (arrow).

Figure 3 Neuronal density (neurons/cm²) (A), the estimated total neuron number (B) and neurons per ganglion immunoreactive for P2X₂ receptor, nitric oxide synthase, choline acetyltransferase, calretinin, and positive for nicotinamide adenine dinucleotide-diaphorase activity in the ileum myenteric plexus of control and obese mice (C), and densities of Dogiel type I and II neurons immunoreactive for calretinin (D) in control and obese mice. ^aP < 0.05 vs control, mean ± SE, Student’s t-test. NOS: Nitric oxide synthase; ChAT: Choline acetyltransferase; NADH: Nicotinamide adenine dinucleotide.

Figure 4 Cell body profile areas (μm²) of neurons immunoreactive for P2X₂ receptor, nitric oxide synthase, choline acetyltransferase, calretinin and nicotinamide adenine dinucleotide-diaphorase in the ileum myenteric plexus of control and obese groups. ^aP < 0.05 vs control, mean ± SE, Student’s t-test. NOS: Nitric oxide synthase; ChAT: Choline acetyltransferase; NADH: Nicotinamide adenine dinucleotide.

Figure 5 Frequency distribution of neuronal size profiles (μm²) for neurons immunoreactive for P2X₂ receptor (A), nitric oxide synthase (B), choline acetyltransferase (C), calretinin (D), and positive for nicotinamide adenine dinucleotide-diaphorase (E) in the ileum myenteric plexus of control (black bars) and obese (grey bars) groups. NOS: Nitric oxide synthase; ChAT: Choline acetyltransferase; NADH: Nicotinamide adenine dinucleotide; CG: Control group; OG: Obese group.

Figure 6 Ileum myenteric neurons labeled for nicotinamide adenine dinucleotide-diaphorase activity in the control group (A, C) and the obese group (C, D), and spaces between the neurons (asterisk) in the obese group group (B, D). Arrows show stained myenteric neurons. CG: Control group; OG: Obese group.