Ostrowski N L, Stapleton J M, Noble R G, Reid L D
Pharmacol Biochem Behav. 1979 Dec;11(6):673-81. doi: 10.1016/0091-3057(79)90261-2.
The effects of morphine and naloxone were observed after administration to female golden hamsters (Mesocricetus auratus). Large doses of morphine, 80 mg/kg, consistently produced sedation and behavioral depression of responses to nociceptive stimuli. Smaller doses of morphine (e.g., 10 mg/kg), that produced few other behavioral changes, suppressed a measure of female sexual responding. The suppressive effects on sexual behavior were reversed by 4 mg/kg of naloxone. Morphine administered intracerebroventricularly had little effect on sexual responding, even at doses which produced other side effects. Doses of 4 and 8 mg/kg of naloxone in opioid-naive subjects did not reliably alter sexual responding up to 2 hr after administration. These observations lead to the suggestion that morphine produces effects which are incompatible with full sexual functioning in female hamsters.
