Nitric oxide synthase-expressing neurons are area-specifically distributed within the cerebral cortex of the rat

Neuronal nitric oxide synthase produces nitric oxide, a radical involved in neurotransmission as well as in cytotoxicity during stroke and neurodegenerative diseases. In the adult Wistar rat neuronal nitric oxide synthase-positive neurons are inhomogenously distributed along defined cortical areas, with highest densities (18 cells/mm(2)) in cingular area 1, piriform cortex, frontal motor area Fr 2 and in the medial visual association area Oc 2MM. A medium packing density of neuronal nitric oxide synthase neurons (10/mm(2)) characterizes primary sensory areas, whereas retrosplenial cortices contain lowest cell numbers (3-5/mm(2)). The data suggest that functions of certain cortical areas are more dependent on intracortically produced nitric oxide than others, and that cortical injury may cause more severe nitric oxide-related cytotoxicity in areas with higher numbers of neuronal nitric oxide synthase-positive neurons. (C) 1997 IBRO. Published by Elsevier Science Ltd.