EVIDENCE for PARTICIPATION of NITRIC-OXIDE in EXCITATORY NEUROTRANSMISSION in RAT VAS-DEFERENS

Abstract

A depression of the fast, non-adrenergic, and also of the slow, adrenergic, components of muscle contraction in response to intramural nerve stimulation was induced by the blocker of nitric oxide synthase N-G-nitro-L-arginine methyl ester (L-NAME), in rat vas deferens. Effects of exogenous noradrenaline or ATP were not reduced by L-NAME, However, L-arginine also caused an inhibition of electrically induced effects in most of the preparations, contrary to the expectations for a precursor of nitric oxide synthesis. in spite of these difficulties L-arginine antagonized the action of L-NAME. These results indicate that nitric oxide is involved in excitatory nerve-muscle transmission in vas deferens.