Role of nitric oxide in non-adrenergic, non-cholinergic nerve-mediated relaxation in dog duodenal longitudinal muscle strips.

Transmural electrical stimulation caused a relaxation in the dog duodenal longitudinal muscle strips treated with atropine, phentolamine and propranolol, which was abolished by tetrodotoxin. The relaxation was suppressed by oxyhemoglobin and L-NG-nitro-arginine (L-NA), but not influenced by D-NA. Inhibition by L-NA was reversed by L-arginine, but not by D-arginine. The response to transmural electrical stimulation was similar to that caused by nitric oxide or nitroglycerin. Nitric oxide appears to participate importantly in non-adrenergic, non-cholinergic nerve-mediated relaxation.