Mechanism of vagal inhibition of small intestine contraction

The mechanism of inhibition of small intestine contraction in response to weak stimulation of the peripheral end of the vagus nerve cut at the cervical level was studied in experiments on anesthetized dogs. This inhibition can be blocked with arfonade or hexamethonium, atropine, and rausedyl, as well as by combined, but not individual administration of propranolol and dihydroergotoxine. We assume that inhibition is triggered by the release of catecholamines from sympathetic postganglionic terminals in response to activation of their muscarinic receptors induced by acetylcholine released from parasympathetic terminals during excitation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 2, pp. 135–138, February, 2000