Anxiolytics reverse the acceleration of ejaculation resulting from enforced intercopulatory intervals in rats

The enforced interval of copulation (EIC) consists of the artificial prolongation of the interintromission interval, induces a reduction in the number of intromissions preceding ejaculation, and is accompanied by an anxiety like behavioral repertoire. The administration of the benzodiazepine anxiolytics diazepam, chlordiazepoxide, flurazepam, and flunitrazepam produced a dose-dependent inhibition of the EIC effect with a concomitant increase in mounting. These actions were blocked by the central benzodiazepine antagonist Ro 15-1788. The anxiogenic agent beta-carboline Zk 39106 had no effect. Treatment with pentobarbital also produced a blockade of the reduction in the number of intromissions during EIC, whereas muscimol and bicuculline lacked this effect. The serotonergic anxiolytic buspirone reversed the facilitatory action induced by EIC; however, two putative serotonergic antianxiety agents, 8-OH-DPAT and ipsapirone, did not modify or potentiate it, respectively. Finally, the nonanxiolytic serotonergic compounds 5-hydroxytryptophan and TFMPP drastically increased the number of mounts but did not antagonize the reduction of intromissions produced by EIC. These results suggest that an increase in the anxiety levels may be responsible for the excitatory action of EIC on sexual behavior.