Regulation by estradiol of GABAA and GABAB binding sites in the diencephalon of the rat: an autoradiographic study.
Using in vitro quantitative autoradiography we studied the in vivo effects of estradiol on GABAA and GABAB receptors in the rat brain. In all the areas studied (suprachiasmatic nucleus, medial preoptic area, striatum, frontal cortex), estradiol failed to significantly affect the GABAA receptor density. Chronic treatment with estradiol led however in the suprachiasmatic nucleus and the striatum to a decrease in the density of GABAB receptors. GABAB receptor regulation by estradiol was found to be area-specific within the hypothalamus since it was not observed in the medial preoptic area. The down regulation of GABAB receptors in the suprachiasmatic nucleus induced by estradiol treatment might thus explain the inhibitory effect of the steroid on the GABA control of serotonin metabolism we recently reported.
François-Bellan
A M
AM
Laboratoire de Médecine Expérimentale, INSERM U297, Marseille, France.
Segu
L
L
Héry
M
M
D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism; D004027:Diencephalon / Q000187:drug effects / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology* / Q000502:physiology; D005260:Female; D008297:Male; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000378:metabolism*
D011963:Receptors, GABA-A; D004958:Estradiol