Regulation of high-affinity GABAa receptors in specific brain regions by ovarian hormones.
The regulation of 3H-muscimol binding to high-affinity GABAa receptors by estradiol (E) and by progesterone (P) was studied within discrete brain regions using in vitro quantitative autoradiography. Treatment of ovariectomized and adrenalectomized female rats with E resulted in a decrease of muscimol binding only in specific estrogen-sensitive brain regions like the ventromedial nuclei (VMN) of the hypothalamus, the arcuate nucleus (ARC), the medial amygdala and the midbrain central grey (MCG). When administered alone, P had no effect. However, in estrogen-primed females, P increased muscimol binding in both VMN and MCG to levels seen in control animals. Thus, E and P exert opposite effects on the GABAa receptor within these two nuclei. As both hormones facilitate female reproductive behavior as well as the release of luteinizing hormone, present results suggest that E and P affect muscimol binding by different mechanisms.
Schumacher
M
M
Laboratory of Neuroendocrinology, Rockefeller University, New York, N.Y.
Coirini
H
H
McEwen
B S
BS
D000315:Adrenalectomy; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008636:Mesencephalon / Q000187:drug effects / Q000378:metabolism; D009118:Muscimol / Q000378:metabolism; D010052:Ovariectomy; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism
D011963:Receptors, GABA-A; D009118:Muscimol; D011374:Progesterone; D004958:Estradiol