ULTRASTRUCTURAL-LOCALIZATION OF NITRIC-OXIDE SYNTHASE IMMUNOREACTIVITY IN THE FRONTAL-CORTEX OF THE MONKEY

By use of electron microscopic immunocytochemistry with an antiserum against nitric oxide synthase (NOS), we demonstrated that, in the frontal cortex (area 45) of the monkey, NOS was localized both within some axon terminals which synapsed on NOS-negative dendrites and within some dendrites which formed synapses with NOS-negative axon terminals. This finding suggests that nitric oxide can be produced in and released from both pre- and postsynaptic neuronal elements in the monkey cerebral cortex.