André De Schaepdryver

In-vitro study of the enkephalinergic hypothesis for non-adrenergic, non-cholinergic innervation in the cat stomach

It has been suggested that enkephalins are involved in the gastric relaxation induced by stimulation of the non‐adrenergic, non‐cholinergic vagal fibres in the cat stomach. Experiments were therefore performed on strips of cat stomach. With longitudinal and circular gastric fundus and corpus strips from reserpinized cats, non‐adrenergic, non‐cholinergic relaxatory responses could be elicited by transmural electrical stimulation in Tyrode solution containing atropine and 5‐hydroxytryptamine. Morphine, leu‐enkephalin and met‐enkephalin did not influence the tone of the strips or the relaxation evoked by stimulation at 8 Hz, and neither did the opioid antagonist, naloxone. These results do not support the enkephalinergic hypothesis for the non‐adrenergic, non‐cholinergic vagal fibres in the cat stomach.