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.

拟议的研究的目的是采用生物物理方法来了解抗癫痫药针对电压依赖性钠通道的药物通过不同的结合与渠道的不同门控状态。这项工作汇集了实验室的两项研究，一种表征了利多卡因，苯甲胺，卡马西平等药物的状态依赖性相互作用，带有钠通道的Lacosamide，另一个探索钠通道的门控如何调节发射各种哺乳动物中央神经元。抗癫痫药的关键特性是差异与钠通道的不同门控状态结合，但是这如何改变特定种类的发射控制病理神经元活性的中枢神经元知之甚少。例如，较高的亲和力与开放和灭活状态结合会导致使用依赖性，并增加了抑制作用作为通道在动作电位期间通过开放和灭活状态循环。但是，这并不容易解释他们的临床作用，因为使用依赖性可能可以预测更多的潜在抑制GABA能抑制与谷氨酸能兴奋性神经元相比，神经元通常以高频发射的神经元，该神经元通常发射更慢。我们将研究抗癫痫药与神经元通道的门控和探索如何依赖于状态的结合和解关调节各种兴奋性的发射模式和抑制神经元。我们将跟进初步数据，表明卡马西平，苯甲胺和 lamotrigine在抑制较慢的谷氨酸能锥体神经元的发射方面都比快速加巴的GABA能神经元。我们将分析这些药物和其他药物如何（包括新的抗癫痫大麻二酚和一种新颖的，更潜在的卡马西平衍生物）与两者的门控相互作用天然和克隆的钠通道以及产生的钠电流的变化如何修改射击各种兴奋和抑制性神经元的模式，取决于其他的曲目频道。实验设计将将动作电势射击的记录与电压钳结合在一起使用完整的脑切片中的完整神经元分析下面的钠电流，急性解离神经元和异源表达的克隆通道。关键特征将是研究动作潜力在37°C下发射，通道门控动力学和药物作用。