NADPH-DIAPHORASE ACTIVITY IN PIGLET INTESTINAL-MUCOSA

The distribution of the enzyme synthesizing nitric oxide (NO) has been characterized in several mammalian enteric nervous systems. Two metho ds, immunohistochemical staining, employing anti-nitric oxide synthase antibodies, and histochemical localization of NADPH-diaphorase (NADPH -D), have given the same results. On the other hand, few studies have investigated nitric oxide synthase (NOS) in the gastrointestinal mucos a. Our study demonstrated the presence and distribution of the enzyme, NADPH-D, throughout all layers of the neonatal piglet intestinal trac t. In the neonatal piglet, NADPH-D activity was found in nerve fibers parallel to the circular and to the longitudinal muscles and in the ga nglion cells of Auerbach's plexus. However, the majority of NADPH-D ac tivity was localized to the mucosa, Furthermore, the most intense acti vity in the mucosa was observed in villous epithelial cells, Other muc osal cells which were NADPH-D positive included the glandular epitheli um and crypt cells. In addition, glandular epithelium in the deeper su bmucosa had very strong NADPH-D activity. Our results support the hypo thesis that locally produced NO mediates physiological functions in th e intestinal mucosa and submucosa.