NADPH DIAPHORASE NEURONS ARE EVENLY DISTRIBUTED THROUGHOUT CAT NEOCORTEX IRRESPECTIVE OF FUNCTIONAL SPECIALIZATION OF EACH REGION

USING NADPH diaphorase histochemistry as a marker for nitric oxide syn thase we investigated the possible sites of nitric oxide synthesis in cat cerebral neocortex. Intensely stained neurones were found mainly i n the deep layers of the neocortex and underlying medulla. Virtually a ll neurones in the cerebral medulla were NADPH diaphorase positive. Th e density of diaphorase neurones was estimated in the cortex/medulla b order zones of each neocortical gyrus. Diaphorase neurones were evenly distributed throughout the neocortex and no significant statistical d ifference between gyri was observed. These findings indicate that the density of diaphorase neurones is irrespective of functional specializ ation of each region and are more in line with the hypothesis that NAD PH diaphorase neurones are involved in the control of local cortical b lood flow.