Enhancement of sexual motivation in male rats by yohimbine.

Yohimbine hydrochloride, an alpha 2-adrenoceptor antagonist, increased sexual motivation in male rats as evidenced by increased mounting performance in mating tests conducted after genital anesthetization, increased percentage of male rats ejaculating in their first heterosexual encounter, and induction of copulatory behavior in sexually inactive male rats. These observations lead to the suggestion that alpha-adrenoceptors are important modulators of sexual arousal in intact male rats. These results indicate that pharmacological treatment of sexual (libido) dysfunction may be useful.