Abstract
The effect of cyproterone acetate (CA) was studied on the autonomic transmission and smooth muscle function of the rat vas deferens. In the CA-treated vas deferens, the endogenously released noradrenaline (NA) in response to electrical field stimulation or exogenously administered NA produced rhythmic contractions (lacking a tonic component) which were abolished by prazosin – a preferential postjunctional α-adrenoceptor blocker. The biphasic nature of the nonadrenergic response elicited on electrical field stimulation in CA-treated rats remained unaltered. Like in controls, yohimbine potentiated this response thereby demonstrating the presence of functional presynaptic α-adrenoceptors (inhibitory in nature). The postjunctional alteration on the membrane function appears to be specific to adrenergic stimulation alone, since both tonic and phasic components were demonstrated in the responses resulting from nonadrenergic stimulation or those produced by barium chloride.