Noradrenaline-serotonin interactions in the control of sexual behavior in the male rat: DSP4-induced noradrenaline depletion antagonizes the facilitatory effect of serotonin receptor agonists, 5-MeODMT and lisuride.

The present communication reports how depletion of central noradrenaline neurons of DSP4 treatment antagonizes the facilitatory actions of 5-MeODMT and lisuride on male rat sexual behavior. In males with intact noradrenaline, 5-MeODMT facilitated sexual behavior by reducing the number of intromissions required for ejaculation; inhibitory actions were also noted, since 5-MeODMT prolonged intromission and ejaculation latencies. In DSP4-pretreated animals the inhibitory effect of 5-MeODMT remained unchanged, whereas its facilitatory action was abolished. Consistent with previous research, lisuride also reduced intromission frequency prior to ejaculation. This facilitation of sexual behavior was not observed in DSP4-treated animals. In the male rat, ejaculations following the first have a lower latency and are preceded by a lower number of intromissions. This naturally occurring facilitation of sexual behavior was not prevented by DSP4-induced noradrenaline depletion. Our results suggest that serotonin and noradrenaline interact in the control of sexual behavior in the male rat.