Localization of age-related changes in NADPH-diaphorase activity in pancreatic neurons

The distribution of NADPH-diaphorase activity in the pancreatic neurons of neonatal, adult and aging rats was investigated using histochemistry. In the neonates, only 40% of the neuronal population showed NADPH-diaphorase labelling, and there was variation in the intensity of labelling ranging from light to heavy staining. In the young and mature adults, 95% of the neurons were labelled for NADPH-diaphorase activity, with most of the neurons being heavily labelled for the enzyme in the older animals. Immediately after birth, the pancreatic neurons found were small clusters of smaller sized cells compared with those observed in the mature adults. Their number reached the adult level by the third month after birth; this was maintained throughout the mature adult phase and subsequently decreased in the aging rats.