Enzyme- and immunohistochemical localization of nitric oxide synthase in nerves of the porcine pancreas

The distribution of nitric oxide synthase (NOS) in neuronal and non-neuronal porcine pancreatic tissues was examined using nicotinamide adenine dinucleotide hydrogen phosphate diaphorase (NADPHd) enzymehistochemistry and neuronal type NOS immunohistochemistry. NOS-containing perikarya were regularly discernible in the pancreatic ganglia, whereas positive thin nerve fibers appeared with in nerve bundles of the interlobular spaces and as thin varicose fibers in the vicinity of pancreatic blood vessels. Vascular endothelium showed intense staining for NADPHd and most of the islet cells were NOS immunoreactive. The above morphological findings indicate that nitrergic innervation of the porcine pancreas is very similar to that of the pancreata of other mammalian species and suggest that nitric oxide of both neuronal and extraneuronal origin may regulate blood flow and secretion of the porcine pancreas. (C) 2000 Published by Elsevier Science Ireland Ltd.