Identification of NADPH- (nitric oxide synthase-) positive neurons in the gastrointestinal tract of the rat

The pattern of distribution of NADPH-diaphorase positive neurons in the intrinsic nerves of the gastrointestinal tract (GIT) and pancreas of the rat was investigated using enzyme histochemical technique. Different segments of the GIT and pancreas were taken from rats and processed for tile the presence of NADPH-diaphorase, an enzyme that shows the specific sites of nitric oxide. Most of the intrinsic nerves of the GIT were stained positively for NADPH. These NADPH-diaphorase positive neurons are multipolar in shape and grouped into ganglia in the submucous and muscular layers. Their processes lie parallel to the long axis of the smooth muscle fibres of the GIT. The NADPH-diaphorase-positive nerves ill the pancreas were found around the basal surfaces of pancreatic acinar tissue. It is concluded that tile GIT and pancreas have numerous NADPH-diaphorase-(NOS-) positive intrinsic nerves. These bioactive agents which regulate the production of nitric oxide may play significant roles in gastrointestinal and pancreatic function.