Dopamine and sexual behavior in the male rat: a reevaluation

Abstract

In castrated male rats treated with a low dose of testosterone propionate (0.40 mg/kg per week), the dopamine agonists amphetamine and amfonelic acid reduced mount latency without affecting other aspects of sexual behavior. Apomorphine, in doses between 0.05 and 0.15 mg/kg, and 1-DOPA 5-45 mg/kg + carbidopa 50 mg/kg, lacked effect on sexual behavior. Both amphetamine and amfonelic acid increased locomotor activity in a dose-dependent manner. Apomorphine, in the lowest dose, produced a reduction whereas the higher doses of this drug as well as all doses of 1-DOPA lacked effect on this behavior. In castrated animals implanted with a testosterone-filled Silastic capsule, showing a level of sexual activity indistinguishable from that of intact animals, amphetamine and amfonelic acid did not affect sexual behavior. The dopamine receptor antagonists haloperidol and cis(Z)-flupentixol reduced sexual behavior, whereas pimozide was without effect in the dose range used. The doses of haloperidol and flupentixol that were required to reduce sexual activity were such that they also affected motor execution measured in a treadmill test. It is suggested that increased dopaminergic neurotransmission may stimulate sexual behavior in an indirect way, augmenting behavioral arousal. The inhibitory effects of dopamine antagonists could be explained either by a reduced arousal level or by motor deficiencies.

Lack of opioid or dopaminergic effects on unconditioned sexual incentive motivation in male rats.

“…For example, it has been reported that exploratory behaviors were much enhanced by amphetamine and amfonelic acid, whereas behaviors directed toward the female, like genital exploration, remained unaffected (Ågmo & Picker, 1990). The inhibitory effects of dopamine antagonists reported in numerous studies can be attributed to motor deficiencies produced by the drugs (Ågmo & Ferna ´ndez, 1989;Ahlenius & Larsson, 1990).…”

Effects of methamphetamine on sexual performance and compulsive sex behavior in male rats

“…However, the number of mounts and intromissions were not affected, suggesting that Meth did not disrupt erectile function. Previous studies examining the effects of acute psychostimulant exposure on sexual behavior have been contradictory and either report the facilitation of sexual behavior (Bignami 1966;Butcher et al 1969) or no effect (Agmo and Fernandez 1989;Agmo and Villalpando 1995). Specifically, acute administration of D-amphetamine (Amph; i.p.…”

Excitotoxic lesions of the nucleus paragigantocellularis facilitate male sexual behavior but attenuate female sexual behavior in rats

“…The mean latency to begin mating and the post-ejaculatory interval were not altered by nPGi lesions suggesting that the nPGi is not involved in the expression of these behaviors. Indeed, these behaviors are thought to be under the control of upstream sites (Phillips-Farfan and Fernandez-Guasti, 2009), particularly those associated with MPOA and the mesolimbic dopamine reward system (Agmo and Fernandez, 1989, Hull et al, 1995, Guevara et al, 2008, Kleitz-Nelson et al, 2010). Therefore, nPGi lesions would not be expected to produce any changes in these measures.…”