Abstract
Nitric oxide (NO) has been identified as a very important relaxation transmitter for mammalian intestinal smooth muscle, NADPH has been used as a maker for neuronal nitric oxide synthase. In the present study, NADPH histochemical staining was used to identify the distributions and origins of nitric oxide in the intestine and rectum of the aganglionosis rats. Seventeen rats, aged 17-22 days old, were obtained and perfused with 4% paraformaldehyde following pentobarbital anesthesia. The enlarged and trasitional intestine which were from the small intestine, the constricted intestine, and the rectum were processed independently. The parasympathetic ganglia, pelvic ganglia were also isolated from the animals and processed for NADPH. In control animals, mesh network like NADPH was identified in the small intestine, large intestine, and rectum. NADPH was present at soma and axons in the myenteric ganglia. NADPH was present at 70〜90% of the ganglion cells. The cell size measured between 17 and 25 μm. Proximal dendlides were positive. It was present at axons and the most neurons in the ganglia and at axons in the circular muscles. In contrast, NADPH was not identified at the constricted part of intestine of the aganglionosis rats (AGR). Mesh networks of the NADPH at myenteric plexus at the proximal bowel segment from the constricted intestine, which is not different from the control animals. Large bundle of NADPH positive fibers were identified at extrinsic part of the distal end of the colon and rectum of the AGR. In both AGR and control animals. NADPH positive neurons were identified from the pelvic ganglia which innervate urinary bladder and colon. These results suggested that the constriction of the intestine at the AGR might be due to lack of NO activities.
