Mayer M L, Higashi H, Gallagher J P, Shinnick-Gallagher P
Brain Res. 1983 Feb 7;260(2):233-48. doi: 10.1016/0006-8993(83)90677-7.
Intracellular recording techniques were used to study the response of cat vesical pelvic ganglion neurones loaded with permeable anions to the application of GABA in vitro. In 106/127 neurones GABA evoked a biphasic response, the initial phase of which was depolarizing and associated with a conductance increase; the latter phase was hyperpolarizing and associated with a conductance decrease. The GABA evoked hyperpolarization and conductance decrease were related and behaved as though generated by closure of ion channels open in the resting membrane. The hyperpolarization had a strong inhibitory action on both spontaneous activity, and excitation evoked by depolarizing current injection and pre-synaptic nerve stimulation. Ion substitution experiments suggest that the conductance decrease is primarily to chloride ions, although other ionic species may contribute. Short iontophoretic applications of GABA-evoked monophasic depolarizing excitatory responses, even during the hyperpolarizing response evoked by perfusion of GABA, suggesting no cross-desensitization between the mechanisms generating the initial and late phases of the biphasic response.
采用细胞内记录技术，在体外研究了加载可渗透阴离子的猫膀胱盆神经节神经元对γ-氨基丁酸（GABA）应用的反应。在127个神经元中的106个中，GABA诱发了双相反应，其初始阶段是去极化的，并与电导增加相关；后一阶段是超极化的，并与电导降低相关。GABA诱发的超极化和电导降低是相关的，其表现就好像是由静息膜中开放的离子通道关闭所产生的。超极化对自发活动以及去极化电流注入和突触前神经刺激所诱发的兴奋均具有强烈的抑制作用。离子替代实验表明，电导降低主要是针对氯离子的，尽管其他离子种类可能也有贡献。即使在GABA灌注诱发的超极化反应期间，GABA的短程离子电泳应用也会诱发单相去极化兴奋性反应，这表明双相反应的初始和晚期阶段产生机制之间不存在交叉脱敏现象。
