RESPONSES TO GABA BY ISOLATED INSECT NEURONAL SOMATA - PHARMACOLOGY AND MODULATION BY A BENZODIAZEPINE AND A BARBITURATE
RESPONSES TO GABA BY ISOLATED INSECT NEURONAL SOMATA - PHARMACOLOGY AND MODULATION BY A BENZODIAZEPINE AND A BARBITURATE
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DOI：
10.1016/0006-8993(87)91411-9
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发表时间：
1987-01-20
期刊：
影响因子：
2.9
通讯作者：
BENSON, JA
中科院分区：
文献类型：
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作者：
LEES, G;BEADLE, DJ;BENSON, JA
从飞蝗（Locusta migratoria）和聚集血吸虫（Schistocerca gregaria）的胸神经节机械分离的神经元胞体在体外存活数小时，并进行电流和电压钳位以记录由γ的短暂压力施加诱发的反应。氨基丁酸（GABA）在各种调节剂的存在下。GABA和蝇蕈醇的应用，但不是巴氯芬，产生了超极化和并发的膜电导增加。在-65 mV时，这种反应背后的电流发生逆转，在所有测试的细胞中被诱发，并显示出向外整流。在74个蝗虫神经元中的6个中，GABA和蝇蕈醇诱发了双相反应，但在血吸虫神经元中没有。在所有神经元中观察到的GABA诱发电流的初始快速相是无法区分的。反应的其余主要、缓慢和持续时间长的成分是在0至-80 mV的膜电位范围内的内向电流，随超极化而增加。GABAA拮抗剂荷包牡丹碱和pitrazepin对快速GABA反应没有影响，而印防己毒素是快速和缓慢GABA反应的有效阻断剂。氟硝西泮增强了高达70%的快速反应的幅度，而不增加其持续时间。戊巴比妥钠增强快速GABA反应的幅度和持续时间。我们得出结论，蝗虫胸神经元GABA受体/通道复合物类似于脊椎动物GABAA受体在具有相关的调节受体网站的苯二氮卓类和acetylituates，但不同的GABA受体本身的药理学方面。
Mechanically dissociated neuronal somata from the thoracic ganglia of Locusta migratoria and Schistocerca gregaria were viable in vitro for hours and were current- and voltage-clamped to record the responses evoked by brief pressure applications of .gamma.-aminobutyric acid (GABA) in the presence of various modulators. The application of GABA and muscimol, but not baclofen, produced a hyperpolarization and concurrent increase in the membrane conductance. The current underlying this response reversed at -65 mV, was evoked in all cells tested and showed outward rectification. In 6 of 74 Locusta neurones but not in the neurones of Schistocerca, GABA and muscimol evoked a biphasic response. The initial, fast phase was indistinguishable from the GABA-evoked current seen in all neurones. The remaining predominant, slow and long-duration component of the response was an inward current over the membrane potential range 0 to -80 mV, increasing with hyperpolarization. The GABAA antagonists bicuculline and pitrazepin were without effect on the fast GABA response while picrotoxin was a potent blocker of both the fast and the slow GABA responses. Flunitrazepam enhanced the amplitude of the fast response by up to 70% without increasing its duration. Sodium pentobarbital enhanced both the amplitude and the duration of the fast GABA response. We conclude that the locust thoracic neuronal GABA receptor/channel complex resembles the vertebrate GABAA receptor in having associated modulatory receptor sites for benzodiazepines and barbituates, but differs from it in terms of the pharmacology of the GABA receptor itself.