Localization of NADPH diaphorase, a histochemical marker for nitric oxide synthase, in the mouse spinal cord

NADPH diaphorase-reactive neurons and fibres are present within the entire spinal cord. Moderately to strongly stained neurons were found in the dorsal horn, in particular in lamina III, as well as around the central canal. A dense accumulation of stained neurons was localized in putative preganglionic sympathetic and parasympathetic nuclei. The somatic motor neurons of the ventral horn were found unlabelled. In view of the recently established identity of NADPH diaphorase with nitric oxide synthase, these results suggest that nitric oxide is involved in sensory and autonomic information processing in the spinal cord.