A non-adrenergic inhibitory innervation in the rat stomach.

The inhibitory response to nerve stimulation was studied in three isolated preparations of the rat stomach. Bethanidine and guanethidine in doses sufficient to block adrenergic neurotransmission reduced but never abolished the inhibitory response to field stimulation of the rat stomach strip. In similar concentration of these drugs, the response to vagus nerve stimulation was diminished; higher doses of blocking agent abolished this response. Relaxation to both field and vagus nerve stimulation could be evoked in stoamchs removed from rats which had received sufficient reserpine to deplte tissue stores of noradrenaline. The response to vagus nerve stimulation was abolished by each of three known ganglion blocking agents. These results show that the rat stomach contains a non-adrenergic inhibitory innervation which is probably the final stage in a vagal pathway.