Wong E H, Leeb-Lundberg L M, Teichberg V I, Olsen R W
Brain Res. 1984 Jun 15;303(2):267-75. doi: 10.1016/0006-8993(84)91213-7.
gamma-Aminobutyric acid (GABA) increases the rate of 36Cl- efflux from preloaded rat hippocampal slices in a dose-dependent manner (EC50: 400 microM). This action has the pharmacological specificity expected of activation of GABA receptors in that it is mimicked by the agonists muscimol and 3-aminopropanesulfonic acid, and blocked by the antagonists bicuculline and picrotoxinin. GABA uptake inhibitors, nipecotic acid and 2,4-diaminobutyric acid, fail to increase 36Cl- flux. Pentobarbital produces a dose-dependent activation (EC50 = 1.5 mM) of 36Cl- efflux with maximal response greater than that of GABA. The effect of pentobarbital can be mimicked by 1,3-dimethylbutylbarbiturate, secobarbital, (+)hexobarbital but not (-)hexobarbital, and is blocked by bicuculline and picrotoxinin. Pentobarbital and the other active barbiturates also potentiate the action of GABA. Phenobarbital does not have any effect independently or in combination with GABA. It is suggested that GABA increases 36Cl- permeability by activation of a postsynaptic receptor which is in turn functionally coupled to a barbiturate receptor.
γ-氨基丁酸（GABA）以剂量依赖性方式（EC50：400微摩尔）增加预先加载的大鼠海马切片中36Cl-的流出速率。这种作用具有激活GABA受体所预期的药理学特异性，因为它被激动剂蝇蕈醇和3-氨基丙烷磺酸模拟，并被拮抗剂荷包牡丹碱和印防己毒素阻断。GABA摄取抑制剂尼克酸和2,4-二氨基丁酸不能增加36Cl-通量。戊巴比妥产生剂量依赖性的36Cl-流出激活（EC50 = 1.5毫摩尔），最大反应大于GABA。戊巴比妥的作用可被1,3-二甲基丁基巴比妥酸盐、司可巴比妥、（+）己巴比妥而非（-）己巴比妥模拟，并被荷包牡丹碱和印防己毒素阻断。戊巴比妥和其他活性巴比妥类药物也增强GABA的作用。苯巴比妥单独或与GABA联合使用均无任何作用。提示GABA通过激活突触后受体增加36Cl-通透性，而该受体又在功能上与巴比妥类受体偶联。
