Characterization of Putative β-AdrenoCeptors in the Myometrium of the Pregnant Ewe: Correlation Between the Binding of [3H] Dihydroalprenolol and the Inhibition of Myometrial Contractility In Vitro

beta-Adrenoceptors in the myometrium of the pregnant ewe were studied both functionally and by radioligand binding techniques using [3H] dihydroalprenolol (DHA). Spontaneous contractile activity in vitro was inhibited by beta-adrenoceptor agonists in a stereoselective manner; the order of potency suggested a beta 2-adrenoceptor was involved. The effects of salbutamol were antagonized competitively by propranolol but the antagonism demonstrated …