Jüptner M, Jussofie A, Hiemke C
Institut für Physiologische Chemie, Universitätsklinikum Essen, Germany.
J Steroid Biochem Mol Biol. 1991 Feb;38(2):141-7. doi: 10.1016/0960-0760(91)90119-p.
The specific binding of tritiated muscimol to gamma-aminobutyric acid (GABA) receptor sites was studied in distinct brain areas of female rats during different endocrine states. In diestrous rats with intact ovaries the highest receptor densities were found in the cortex (10.24 pmol/mg protein) and the lowest concentrations in the mediobasal hypothalamus (3.29 pmol/mg protein). Four weeks after removal of the ovaries, the number of binding sites was enhanced up to 2.4-fold in all brain areas investigated: the preoptic brain area, mediobasal hypothalamus, corticomedial amygdala, and cerebral cortex. The affinity of the binding sites remained unchanged. Substitution of estradiol and progesterone reduced the number of binding sites to values seen before ovariectomy. The induction of an afternoon surge of LH by estradiol that could be blocked by enhancing the GABAergic tone was accompanied by a distinct reduction in Bmax in the preoptic area in the morning. These results give evidence that ovarian hormones modulate GABAergic neurotransmission by regulation of GABAA receptor synthesis or degradation.
在处于不同内分泌状态的雌性大鼠的不同脑区，研究了氚标记的蝇蕈醇与γ-氨基丁酸（GABA）受体位点的特异性结合。在卵巢完整的动情间期大鼠中，皮质中发现最高的受体密度（10.24 pmol/mg蛋白质），而在中基底下丘脑的浓度最低（3.29 pmol/mg蛋白质）。卵巢切除四周后，在所有研究的脑区（视前脑区、中基底下丘脑、皮质内侧杏仁核和大脑皮质）中，结合位点的数量增加至2.4倍。结合位点的亲和力保持不变。雌二醇和孕酮的替代将结合位点的数量降低至卵巢切除术前的水平。可通过增强GABA能张力来阻断的雌二醇诱导的下午LH峰，在上午视前区伴随着Bmax的明显降低。这些结果证明，卵巢激素通过调节GABAA受体的合成或降解来调节GABA能神经传递。
