Specific involvement of central 5-HT1A receptors in the mediation of male rat ejaculatory behavior

The aminotetralin 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), pharmacologically characterized as a 5-HT1A receptor agonist, produces a pronounced decrease in ejaculation latency in the male rat. Stimulation of 5-HT receptors by a pharmacologically induced increase in the synaptic availability of 5-HT has been shown to produce the opposite effect. The 8-OH-DPAT-induced decrease in ejaculation latency is specific for this compound, and some chemically related ergot derivatives. In this paper we review the evidence in support for stimulation of serotonergic autoreceptors of the 5-HT1A receptor subtype as a mechanism of action for effects by 8-OH-DPAT on male rat ejaculatory behavior. We also present the questions posed by the fact that quinpirole and lisuride both produce 8-OH-DPAT-like effects on male rat ejaculatory behavior. The effects by quinpirole, lisuride or 8-OH-DPAT are not sensitive to pretreatment with the DA D-2/3 receptor antagonist raclopride. Continued studies will show whether the effects of quinpirole and lisuride can be related to stimulation of 5-HT1A receptors, or if all these compounds have as yet undefined common properties.