SLOW INACTIVATION OF SODIUM CHANNELS

描述：本提案的广泛、长期目标是 以表征各部分的结构-功能关系， 控制慢失活及其相互作用的钠通道 与其他渠道功能，并最终定义如何 通道结构的异常可能导致疾病状态， 癫痫和周期性麻痹 具体目的是：1）构建、表达和比较野生型和 突变的钠离子通道，以确定通道分子的哪一部分 控制缓慢激活; 2）确定 缓慢失活和活化之间的相互作用。 这项建议的健康相关性在于其适用于 神经元兴奋性 神经元的一个关键因素 过度兴奋（可能导致癫痫和其他疾病 涉及失去对细胞兴奋性的控制）是去极化 在中点处，F（Vh）曲线的斜率增加，这导致 可用于激活的通道数量增加， 静息电位 将记录宏观钠电流和单通道电流 来自表达野生型和突变型钠通道的非洲爪蟾卵母细胞 使用膜片钳技术。 慢失活特性， 包括F（Vh）曲线的化合价和中点以及慢 灭活开始和恢复率将比较 野生型和钠通道 变种人 激活电压依赖性 快速失活动力学和通道渗透 还将监测财产，以评估其他潜在的 引入突变的后果。

DESCRIPTION: The broad, long-term objectives of this proposal are to characterize the structure-function relationship of the parts of sodium channels that control slow inactivation and its interactions with other channel functions, and to ultimately define how abnormalities in channel structure might lead to disease states like epilepsy and the periodic paralyses. The specific aims are: 1) to make, express and compare wildtype and mutant sodium channels to determine which part of the channel molecule controls slow activation; and 2) to determine the nature of interaction between slow inactivation and activation. The health-relatedness of this proposal is in its application to neuronal excitability. One critical factor in neuronal hyperexcitability (that could lead to epilepsy and other diseases involving loss of control over cell excitability) is a depolarization in the midpoint and increase in slope of the F(Vh) curve which leads to an increase in the number of channels available for activation from resting potential. Macroscopic sodium currents and single channel currents will be recorded from Xenopus oocytes expressing wild-type and mutant sodium channels using the patch clamp technique. Slow inactivation properties, including valence and midpoint of the F(Vh) curve as well as slow inactivation onset and recovery rates will be compared between wildtype and sodium channel mutants. Activation voltage dependence and kinetics, fast inactivation kinetics and channel permeation properties will also be monitored to assess other potential ramifications of introduced mutations.