Role of oxytocin in the hypothalamic regulation of sexual receptivity in hamsters.
Oxytocin (OXT) has been implicated in the control of a variety of social and reproductive behaviors in several species. The purpose of the present study was to test the hypothesis that OXT activity within the medial preoptic-anterior hypothalamus (MPOA-AH) and the ventromedial hypothalamus (VMH) plays a critical role in the expression of sexual receptivity in Syrian hamsters. The first 2 experiments investigated whether OXT would stimulate sexual receptivity in female hamsters in a dose-dependent manner. A 3rd experiment investigated whether sexual receptivity would be inhibited when endogenous OXT activity was blocked. Microinjection of OXT into the MPOA-AH or the VMH induced sexual receptivity in a dose-dependent manner in ovariectomized (OVX) hamsters primed with estradiol. Microinjection of a selective OXT antagonist, d(CH2)5[Tyr(Me)2Thr4,Tyr-NH29] ornithine vasotocin into the MPOA-AH or the VMH significantly reduced the levels of sexual receptivity exhibited by OVX hamsters administered estradiol and progesterone. These findings support the hypothesis that OXT activity in the MPOA-AH and the VMH plays an important role in the regulation of sexual receptivity in hamsters.
Whitman
D C
DC
Department of Biology, Georgia State University, Atlanta 30302-4010, USA.
Albers
H E
HE
D000818:Animals; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D007032:Hypothalamus, Anterior / Q000502:physiology; D007033:Hypothalamus, Middle / Q000502:physiology; D008297:Male; D008647:Mesocricetus; D008845:Microinjections; D010121:Oxytocin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011301:Preoptic Area / Q000502:physiology; D011374:Progesterone / Q000494:pharmacology; D012726:Sexual Behavior, Animal / Q000187:drug effects*
D011374:Progesterone; D004958:Estradiol; D010121:Oxytocin