VISUALIZATION OF NITRIC-OXIDE RELEASED BY NERVE-STIMULATION

We have visualised nitric oxide (NO) released from the electrically st imulated myenteric plexus and hypogastric nerve. NO was visualised by a reaction with luminol and hydrogen peroxide to generate photons whic h were counted using a microscope coupled to a photon counting camera. Electrical stimulation of the tissues induced an increase in photon c ounts which was frequency-dependent and prevented by inhibition of the NO synthase or by tetrodotoxin. The light emitted during nerve stimul ation was not only observed at the nerve terminals but also at the axo n and soma. Our results indicate that NO released from the whole nerve cell may affect target cells surrounding all parts of the nitrergic n euron. Thus, NO functions as a unique mechanism of synaptic and non-sy naptic communication in the nervous system. (C) 1997 Wiley-Liss, Inc.