Colocalisation of NADPH-diaphorase with nitric oxide synthase and vasoactive intestinal polypeptide in newborn pancreatic neurons.

Numerous NADPH-diaphorase positive neurons were localised in the pancreatic ganglia cultured from newborn guinea pigs. Most of these ganglia were found in the head region of the pancreas. A majority of the labelled neurons occurred in groups, although solitary neurons were also present. NADPH-diaphorase labelling was localised mainly in the cell cytoplasm and its processes, but not within the nucleus. There were more nitric oxide synthase (NOS)-immunoreactive neurons in culture as compared with those positive for NADPH-diaphorase. NADPH-diaphorase activity has been colocalised with NOS and vasoactive intestinal polypeptide (VIP) in a subset of neurons in culture. Colocalisation of NADPH-diaphorase with NOS and VIP in cultured neurons was not restricted to the cell body but also to the proximal and distal processes. Some of these labelled processes made contacts with exocrine acinar and endocrine cells. It is concluded that neuronal nitric oxide (NO) may be influencing the secretory roles of the pancreas, thereby participating in homeostasis.