Pharmacological manipulation of anxiety and male rat sexual behavior.

Several anxiolytic/anxiogenic treatments were evaluated on male rat sexual behavior. The anxiolytic drug diazepam (1.0 mg/kg) inhibited copulatory behavior as indicated by an increase in the number of mounts preceding ejaculation, prolongation of the ejaculation latency and the postejaculatory interval. These changes were not accompanied by alterations in motor coordination as tested on a treadmill apparatus. A lower dose of diazepam (0.5 mg/kg) did not affect the sexual behavior. The anxiogenic drug Zk 39106 (2 and 4 mg/kg) facilitated the copulatory behavior by reducing the number of intromissions preceding ejaculation. A higher dose of Zk 39106 (8 mg/kg) inhibited sexual behavior. The selective benzodiazepine antagonist, Ro 15-1788 (5 and 10 mg/kg), did not modify male sexual behavior, but effectively antagonized the effects of Zk 39106 and diazepam. The administration of Zk 39106 (2 mg/kg) reversed the inhibitory action of diazepam (1.0 mg/kg) on copulation; however, diazepam did not prevent the facilitory effect of Zk 39106. The data are discussed in terms of the possible relationship existing between anxiety and masculine sexual behavior.