Inhibition of mating by naloxone or morphine in recently castrated, but not intact male rats.
Administration of naloxone (SC 5 mg/kg) significantly reduced ejaculation and mounting in male rats in the weeks following castration. A similar effect was obtained by injecting morphine (SC 1 or 5 mg/kg). In contrast, the same dosages of naloxone or morphine did not affect the sexual performance of gonadally intact males. Opioid peptides may contribute to the temporary persistence of sexual behavior in testosterone-deficient male mammals, in which incentive qualities of the female partner are an important determinant of sexual arousal.
D000818:Animals; D002369:Castration; D004542:Ejaculation / Q000187:drug effects; D005260:Female; D005837:Genitalia, Male / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000187:drug effects*
D009270:Naloxone; D009020:Morphine