ANTICONVULSANT REGULATION OF GABA CHLORIDE CHANNELS

为了了解其生理和药理作用 苯二氮卓类和巴比妥类抗惊厥药的性质 将研究GABA/苯二氮卓/-巴比妥酸配体和 受体相互作用。我们将描述GABA引起的单次 通道氯电流及其调节 苯二氮卓类和巴比妥酸受体激动剂及其逆转药 激动剂。 苯二氮卓类药物和巴比妥类药物的抗惊厥活性可 部分通过增强神经元对GABA的抑制而实现的 兴奋性。细胞内记录显示这种增强 通过增加和/或延长GABA诱发的整体 细胞氯电流，但机制似乎不同 人们对此知之甚少。整个细胞的氯电流是 由通过通道传导的许多较小的离子电流组成 在膜和通道短暂地打开和关闭时 激活了。了解抗惊厥药物作用的关键 它们的不同反应是研究它们之间的耦合 配基结合及其门控特性或动力学行为 氯离子通道的打开和关闭。配体可能会改变 通过修改通道开闭频率 受体结合和/或改变通道的物理特性 门控。细胞内记录技术和噪声频率 分析不能解决复杂的行为和机制 频道选通。新开发的膜片钳技术，它 启用单离子通道电流的直接记录，将 用于对小鼠脊髓和皮质进行研究 原代分离细胞培养中的神经元。重点将是 放在电导的鉴定和表征上 及其与配体结合和相互作用的机制 机场的开启和关闭的规管 GABA/苯二氮卓/巴比妥酸盐氯离子通道复合体。 其目标是确定苯二氮类药物和巴比妥类药物 抗惊厥药物增强GABA抑制的研究 它们的作用是单离子通道/受体水平。

In an effort to understand the physical and pharmacologic properties of benzodiazepine and barbiturate anticonvulsants, we will investigate GABA/benzodiazepine/-barbiturate ligand and receptor interactions. We will characterize GABA evoked single channel chloride currents and the regulation of these currents by benzodiazepine and barbiturate receptor agonists and inverse agonists. The anticonvulsant activity of benzodiazepines and barbiturates may in part be mediated by potentiating GABA inhibition of neuronal excitability. Intracellular recordings have shown the potentiation to be produced by increasing and/or prolonging GABA-evoked whole cell chloride currents but the mechanisms appear to be different and are poorly understood. The whole cell chloride currents are composed of many smaller ionic currents conducted through channels in the membrane and the channels open and close briefly when activated. A key to understanding how the anticonvulsants effect their differential response is to investigate the coupling between ligand binding and the gating properties or kinetic behavior of opening and closing of the chloride channel. Ligands may alter the frequency of channel opening and closing through modification of receptor binding and/or alter the physical properties of channel gating. Intracellular recording techniques and noise frequency analysis cannot resolve the complex behavior and mechanisms of channel gating. Newly developed patch clamp techniques, which enable direct recording of single ion channel currents, will be used in performing studies on mouse spinal cord and cortical neurons in primary dissociated cell culture. Emphasis will be placed upon identification and characterization of the conductances involved and the mechanisms of action between ligand binding and the regulation of opening and closing of the GABA/benzodiazepine/barbiturate chloride channel complex. The goal is to establish how benzodiazepine and barbiturate anticonvulsants potentiate GABA inhibition by investigation of their actions ar the single ion channel/ receptor level.