Akema T, Kimura F
Department of Physiology, St. Marianna University School of Medicine, Kawasaki, Japan.
Neuroendocrinology. 1993 Jan;57(1):28-33. doi: 10.1159/000126338.
Effects of selective gamma-aminobutyric acidA (GABAA) and GABAB receptor agonists on noradrenaline (NA)-induced and N-methyl-D-aspartate (NMDA)-induced luteinizing-hormone (LH) secretion were examined in ovariectomized estrogen-primed rats. Experiments were performed in unanesthetized animals bearing chronic intracerebroventricular (i.c.v.) cannulae. I.c.v. injections of NA or NMDA stimulated LH secretion in animals that had received prior i.c.v. injections of saline. The effects of NA and NMDA were significantly attenuated by a prior i.c.v. injection of phentolamine (a selective alpha-adrenergic-receptor blocker) and 2-amino-5-phosphonovaleric acid (a selective NMDA receptor antagonist), respectively. NA-induced LH release was also inhibited by i.c.v. injections of either muscimol (a selective GABAA receptor agonist) or baclofen (a selective GABAB receptor agonist). On the other hand, although muscimol inhibited the effect of NMDA, baclofen did not inhibit but slightly augmented the NMDA-induced release of LH. These results support the hypothesis that both GABAA and GABAB receptors are involved in the GABAergic inhibition of LH secretion, and further suggest that they are probably located at different sites in the neural mechanism regulating LH secretion in the female rat.
在去卵巢并用雌激素预处理的大鼠中，研究了选择性γ-氨基丁酸A（GABAA）和GABAB受体激动剂对去甲肾上腺素（NA）诱导和N-甲基-D-天冬氨酸（NMDA）诱导的促黄体生成素（LH）分泌的影响。实验在未麻醉的、带有慢性脑室内（i.c.v.）套管的动物身上进行。脑室内注射NA或NMDA可刺激那些先前接受过脑室内注射生理盐水的动物的LH分泌。NA和NMDA的作用分别被先前脑室内注射酚妥拉明（一种选择性α-肾上腺素能受体阻滞剂）和2-氨基-5-磷酸戊酸（一种选择性NMDA受体拮抗剂）显著减弱。脑室内注射蝇蕈醇（一种选择性GABAA受体激动剂）或巴氯芬（一种选择性GABAB受体激动剂）也可抑制NA诱导的LH释放。另一方面，虽然蝇蕈醇抑制NMDA的作用，但巴氯芬并不抑制反而略微增强NMDA诱导的LH释放。这些结果支持以下假说，即GABAA和GABAB受体均参与GABA能对LH分泌的抑制作用，并且进一步表明它们可能位于雌性大鼠调节LH分泌的神经机制中的不同位点。
