Effects of apomorphine, (+)-amphetamine, and nialamide on tetrabenazine-induced suppression of sexual behavior in the male rat

It was concluded that monoamines may be critically involved in the control of sexual behavior in the male rat and amphetamine when given alone reduced ejaculatory latency; in combination with TBZ it restored sexual behavior to control levels.

Abstract

Sexual behavior in male rats was abolished after an i.p. injection of 5 mg/kg tetrabenazine (TBZ). Intraperitoneal injections of apomorphine (0.8 mg/kg), amphetamine (0.8 mg/kg), and nialamide (40 mg/kg) antagonized this suppression. Apomorphine, both alone and in combination with TBZ, decreased intromission frequency and increased post-ejaculatory latency, but did not significantly affect ejaculatory latency. Amphetamine when given alone reduced ejaculatory latency; in combination with TBZ it restored sexual behavior to control levels. Nialamide alone had no effect on sexual behavior. In combination with TBZ it increased ejaculatory latency; intromission frequency and the post-ejaculatory interval were unaffected. The results are discussed in terms of the probable mechanisms of action of the drugs investigated. It was concluded that monoamines may be critically involved in the control of sexual behavior in the male rat