IMMUNOHISTOCHEMISTRY OF NITRIC-OXIDE SYNTHASE DEMONSTRATES IMMUNOREACTIVE NEURONS IN SPINAL-CORD AND DORSAL-ROOT GANGLIA OF MAN AND RAT

The presence of nitric oxide synthase in spinal cord and dorsal root g anglia was investigated by immunohistochemistry using antibodies again st the constitutive neuronal form of nitric oxide synthase (NOS). NOS immunoreactivity was present in both man and rat with similar distribu tion, being present in primary sensory neurons of dorsal root ganglia and their afferent terminals in dorsal horn of spinal cord. NOS immuno reactive interneurons were found in the superficial layer of the dorsa l horn, around the central canal and in the intermediolateral cell col umn. NOS immunoreactivity was also present in numerous motoneurons in the ventral horn. The widespread distribution of NOS in both sensory a nd motor nervous system is indicative of the involvement of nitric oxi de in different neural functions.