Abstract
Noradrenaline (0·6–19 μM and phenylephrine (2–130 μM induced contractions in the rat seminal vesicle that were competitively antagonized by the α1-adrenoceptor-selective antagonist corynanthine (120–920 nM). Yohimbine (60–450 nM), an α2 adrenoceptor-selective antagonist, produced a non-competitive antagonism of noradrenaline responses, suggesting that the responses were not α2-adrenoceptor mediated. It is concluded that the rat seminal vesicle has a predominance of α1-adrenoceptors.