State-dependent interaction of antiepileptic drugs with voltage-dependent sodium channels and differential regulation of excitatory and inhibitory central neurons

抗癫痫药物与电压依赖性钠通道的状态依赖性相互作用以及兴奋性和抑制性中枢神经元的差异调节

基本信息

批准号：
10332723
负责人：
BRUCE P BEAN
金额：
$ 47.47万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-02-01 至 2024-01-31
项目状态：
已结题

项目摘要

The goal of the proposed research is to take a biophysical approach to understand how antiepileptic drugs targeted to voltage-dependent sodium channels regulate neuronal firing by differentially binding to different gating states of the channels. The work brings together two lines of research in the laboratory, one characterizing the state-dependent interaction of drugs like lidocaine, phenytoin, carbamazepine, and lacosamide with sodium channels and the other exploring how gating of sodium channels regulates firing of a variety of mammalian central neurons. A key property of antiepileptic drugs is differential binding to different gating states of sodium channels, but how this changes firing of particular kinds of central neurons to control pathological neuronal activity is poorly understood. For example, higher affinity binding to open and inactivated states results in use-dependence, with increased inhibition as channels cycle through open and inactivated states during action potentials. Yet, this does not easily explain their clinical action, because use-dependence might predict more potent inhibition of GABAergic inhibitory neurons, which typically fire at high frequencies, than glutamatergic excitatory neurons, which typically fire more slowly. We will examine how antiepileptic drugs interact with the gating of neuronal sodium channels and explore how state-dependent binding and unbinding regulates the firing patterns of a variety of excitatory and inhibitory neurons. We will follow up preliminary data showing that carbamazepine, phenytoin, and lamotrigine are all more effective in inhibiting firing of slower-firing glutamatergic pyramidal neurons than fast-spiking GABAergic neurons. We will analyze how these drugs and others (including the new anti- epileptic cannabidiol and a novel, more potent carbamazepine derivative) interact with gating of both native and cloned sodium channels and how the resulting changes in sodium current modify the firing patterns of a variety of excitatory and inhibitory neurons in a manner depending on the repertoire of other channels. The experimental design will combine recordings of action potential firing with voltage-clamp analysis of the underlying sodium currents, using intact neurons in brain slice, acutely dissociated neurons, and heterologously expressed cloned channels. A key feature will be to study action potential firing, channel gating kinetics, and drug action at 37 °C.

拟议研究的目标是采用生物物理学方法来了解抗癫痫药物如何靶向电压依赖性钠药物通道通过差异结合来调节神经放电这项工作汇集了实验室的两条研究方向，一种描述利多卡因、苯妥英、卡马西平等药物的状态依赖性相互作用的特征，和带有钠通道的拉科酰胺，另一个探索钠通道的门控如何调节多种哺乳动物中枢神经元的放电是抗癫痫药物的一个关键特性。与钠通道的不同门控状态结合，但这如何改变特定种类的发射中枢神经元控制病理神经元活动的机制尚不清楚，例如较高的亲和力。与开放和失活状态的结合导致使用依赖性，并增加作为通道的抑制然而，这并不能轻易解释它们在动作电位期间的开放和失活状态。临床作用，因为使用依赖性可能预示 GABA 能抑制作用更有效神经元通常以高频率放电，而谷氨酸兴奋性神经元通常以高频率放电我们将研究抗癫痫药物如何与神经元钠通道的门控相互作用。探索状态依赖的结合和解除结合如何调节各种兴奋性的放电模式我们将跟踪显示卡马西平、苯妥英和抑制性神经元的初步数据。拉莫三嗪在抑制放电较慢的谷氨酸能锥体神经元的放电方面比我们将分析这些药物和其他药物（包括新的抗-GABA能神经元）的作用。癫痫性大麻二酚和一种新型、更有效的卡马西平衍生物）与两者的门控相互作用天然和克隆的钠通道以及钠电流的变化如何改变放电各种兴奋性和抑制性神经元的模式取决于其他神经元的全部功能实验设计将动作电位放电的记录与电压钳结合起来。使用大脑切片中急性分离的完整神经元分析潜在的钠电流神经元和异源表达的克隆通道的一个关键特征是研究动作电位。 37°C 下的发射、通道门控动力学和药物作用。