[Effect of morphine on autonomic reflexes induced by stimulation of afferent fibers in the stomach].

In anesthetized cats, afferents of the gastric branch of the dorsal vagal trunk were stimulated (20 Hz, 5-10 V, 1 ms) prior to and after i.v. administration of morphine (1 and 10 mg/kg). Firing rate in sympathetic efferents of the left splanchnic nerve and potentials in smooth muscles of the stomach and small intestine were recorded. Morphine abolished dose-dependently the sympatho-inhibitory effects of the stimulation of vagal afferents. The activating effect of gastric fibers was more pronounced in the intestine than in the stomach. Morphine abolished the activating effects in the intestine. Gastric responses after morphine varied from weak activating to inhibitory ones.