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

拟议研究的目标是采取生物物理方法来了解抗癫痫药物如何 靶向电压依赖性钠通道的药物通过差异性结合 通道的不同选通状态。这项工作汇集了实验室的两条研究路线， 一个是表征药物如利多卡因，苯妥英，卡马西平， 和拉考沙胺与钠通道和其他探索如何门控钠通道调节 各种哺乳动物中枢神经元的放电抗癫痫药物的一个关键特性是差异化 结合到钠通道的不同门控状态，但是这如何改变特定种类的 中枢神经元控制病理性神经元活动的机制知之甚少。例如，更高的亲和力 结合到开放和失活状态导致使用依赖性，增加抑制作为通道 在动作电位期间通过开放和失活状态循环。然而，这并不能很容易地解释他们的 临床作用，因为使用依赖性可能预测GABA能抑制剂的更有效抑制 神经元，通常在高频率下发射，而不是兴奋性神经元，通常 火慢一点。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， 探索状态依赖的绑定和解除绑定如何调节各种兴奋性的放电模式。 和抑制性神经元。我们将跟进初步数据显示，卡马西平，苯妥英， 拉莫三嗪在抑制慢放电海马锥体神经元放电方面都比 GABA能神经元的快速反应我们将分析这些药物和其他药物（包括新的抗- 癫痫大麻二酚和一种新的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由此产生的钠电流变化如何改变放电 各种兴奋性和抑制性神经元的模式，其方式取决于其他神经元的库。 渠道实验设计将联合收割机记录动作电位放电与电压钳相结合 使用急性分离的脑切片中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。一个关键特征将是研究动作电位 在37 °C下的发射、通道门控动力学和药物作用。

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.