Oxytocin improves male copulatory performance in rats

Pharmacology for the Treatment of Premature Ejaculation

“…It was therefore proposed that OT in epididymis promotes spermatozoa transport into the vas deferens during the emission phase of ejaculation. This could explain the facilitation of ejaculation found in copulating rats after systemic delivery of OT (Arletti et al, 1985;Stoneham et al, 1985). Apparently supporting this view is the fact that, in rats as well as in men, plasma levels of OT do not show marked increase during sexual arousal but peak at the time of ejaculation (Stoneham et al, 1985;Carmichael et al, 1987;Murphy et al, 1987).…”

“…Infused into the cerebral ventricle of a male rat free to copulate with a receptive female, OT facilitates ejaculatory behavior by shortening ejaculation latency and postejaculatory refractory period (Arletti et al, 1985). Intracerebroventricular administration of a potent OT antagonist impairs sexual performance in experienced male rats in the presence of a receptive female by decreasing the intromission frequency and abolishing ejaculation at doses failing to modify any other behavioral parameters (Argiolas et al, 1988).…”

Pharmacological analysis of male rat sexual behavior

“…In support of this hypothesis, intracranial injections of oxytocin have been reported to affect copulatory behavior, but with conflicting results. A low dose of oxytocm (1 ng) into the lateral ventricle mimicked the facdltative effects on sexual behavior observed following systemic admxmstratlon [20]; however, higher doses (250 and 500 ng) were found to increase mount and mtromission latencies, and to prolong the postejaculatory refractory period [211]. In a follow-up study, electrolytic lesions of the parvocellular division of the PVN, cell bodies of which project to extrahypothalamic neural regions (reviewed in [208]).…”

“…Several experiments have reported faclhtatwe effects of systemic oxytocm injections on copulatory behavior Intravenous injection of oxytocin decreased ejaculation latency and increased ejaculation number in rabbits [154], though slmdar mject,ons m rats had no effect on copulat,on [133]. However, m another study, mount and mtrom~ss~on latencies were reduced, as were the number of mtrom~sslons and latency to ejaculation following a systemic mject~on of oxytocln in sexually experienced male rats, the incidence of mounting behavior in sexually sluggish male rats was not affected [20] In a recent study, an increase in cerebral spinal fluid concentration of oxytocin was reported following ejaculation in the rat [118]. These findings suggest that oxytocinergic projectlons within the central nervous system may participate in the regulation of coital behavior [118].…”

Increased Fos Expression in Oxytocin Neurons Following Masculine Sexual Behavior

“…Although recent experiments have shown that male copulatory behavior enhances Fos immunoreactivity in several brain areas, we have confined our studies to effects found within the PVN, an area rich in O T and vasopressin (AVP) neurons (25). OT (26,27), AVP (7), corticotropin releasing hormone (CRH) (28), galanin (GAL) (29) and cholecystokinin (30), all synthesized in the PVN, have been implicated in the control of male sexual behavior. The present study uses doublelabel immunocytochemistry to assess whether OT and AVP neurons may be activated, as measured by Fos immunoreactivity, during intromission and ejaculation in male rats.…”