Pharmacological characteristics of the responses of rabbit oviduct to transmural stimulation.

The nature of the response of oestrogen dominant rabbit oviduct to transmural stimulation has been investigated. Both ampulla and isthmus responded to transmural stimulation with a single maintained response. This response was abolished by phentolamine, guanethidine, tetradotoxin and 6-hydroxydopamine showing that it resulted from the release of noradrenaline from adrenergic nerves and an action on alpha receptors. Propranolol had no effect on the responses of circular isthmic muscle suggesting that the beta receptors were relatively unimportant in determining the magnitude of the response. Cocaine failed to potentiate the magnitude of the response to field stimulation but did prolong the duration of the response. UO521, an inhibitor of COMT, had no effect on the responses of circular isthmus to transmural.