Effects of hypothalamic deafferentation on hormonal facilitation of lordosis in ovariectomized rats.
Lordosis response in estradiol benzoate (EB)-progesterone (P) primed castrated female rats was studied after 4 types of deafferentation of the medial hypothalamus. Tests were started 4-5 weeks after the brain surgery and ovariectomy. Anterior deafferentation (half-dome cut) at the level behind the suprachiasmatic nucleus (AD-I) and island isolation of the medial basal hypothalamus (MBH island) were highly effective to suppress lordosis response in EB-P primed females. However, the cuts placed dorsal (AD-II) or posterior (AD-III) to the AD-I were without apparent suppressive effect on the EB-P induced display of lordosis. These results suggest that the anterolateral fiber connection with the MBH may participate in lordosis facilitatory mechanisms in EB-P primed females. When reserpine (R) was injected instead of P to EB-primed rats, R effectively facilitated lordosis response in rats with or without the deafferentation (AD-I or MBH island). This suggests that the MBH is not necessary to facilitate lordosis in EB-R primed rats. The site of action of R in the central nervous system for facilitating lordosis may not be the same as that of P.
D000344:Afferent Pathways; D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D007033:Hypothalamus, Middle / Q000502:physiology*; D011187:Posture; D011374:Progesterone / Q000494:pharmacology; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*
D011374:Progesterone; D004958:Estradiol; D012110:Reserpine