Evidence for involvement of nitric oxide (NO) or a related nitroso-compound in NANC inhibitory neurotransmission in the pigeon oesophageal smooth muscle.

Abstract

In the pigeon oesophageal smooth muscle electrical field stimulation (EFS), in the presence of atropine and guanethidine, evoked TTX-sensitive inhibitory effects on both the electrical and mechanical activity. N(omega)-Nitro L-arginine (L-NA) (0.1-100 microM), an inhibitor of nitric oxide synthase, reduced the inhibitory EFS-evoked effects. Sodium nitroprusside (SNP) (10 microM), a NO-donor, mimicked the effects evoked by EFS. Apamin (1 microM) perfusion did not modify the inhibitory effects induced by SNP. Cystamine (10 microM), a guanylate-cyclase inhibitor, reduced the inhibitory effects elicited by EFS. This study shows a possible role for NO in the non-adrenergic non-cholinergic (NANC) inhibitory responses induced by EFS in the pigeon oesophagus.