MOLECULAR STUDIES OF SODIUM CHANNELS IN SKELETAL MUSCLE

电压门控钠通道负责产生和 电兴奋细胞中动作电位的传播。 钠 通道表现出不同的药理学和功能特性， 是由多基因家族编码的 三个高度同源钠通道 通过cDNA核苷酸序列分析， 序列分析 赞助商的实验室克隆并鉴定了一个完整的- 长cDNA编码骨骼肌中独特的大鼠钠通道cDNA。 这项研究的目标是阐明一个 第二个新的大鼠骨骼肌钠通道基因并制备探针 以确定生物特性差异的结构基础 神经和骨骼肌中的钠离子通道。 具体目标是：1）确定有多少不同的钠通道 通过核苷酸序列分析，大鼠骨骼肌中存在一种亚基 分离全长cDNA并鉴定其功能 使用非洲爪蟾卵母细胞表达系统的性质; 2）确定 大鼠骨骼肌钠离子的细胞和亚细胞定位 通道α亚单位的免疫细胞化学和超微结构 技术，使用针对阿尔法的独特部分的抗体， 亚基肽; 3）确定河豚毒素的分子基础 利用钠通道mRNA分析的TTX敏感性和不敏感性 在TTX敏感成人肌肉和相对TTX抗性胚胎中， 失神经肌肉 在哺乳动物中，钠通道基因的自发突变， 预期会干扰正常神经系统和骨骼肌功能 根据钠通道在信号传导中的关键作用， 信息处理，以及大量的基因参与钠 在许多组织中产生通道蛋白。 这些计划中的研究， 结合我在遗传学方面的经验，将为以下方面提供框架： 探讨假定的肌肉钠通道基因突变在 人的骨骼肌疾病。

The voltage-gated sodium channel is responsible for the generation and propagation of action potential in electrically excitable cells. Sodium channels exhibit different pharmacological and functional properties and are encoded by a multigene family. Three highly homologous sodium channel alpha subunits have been identified in rat brain by cDNA nucleotide sequence analysis. The sponsor's lab has cloned and characterized a full- length cDNA encoding a unique rat sodium channel cDNA in skeletal muscle. A goal of the proposed research is to elucidate the primary structure of a second novel rat skeletal muscle sodium channel gene and to generate probes to determine the structural basis for differences in biological properties of the sodium channels in nerve and skeletal muscle. The specific goals are: 1) to determine how many distinct sodium channel subunits are present in rat skeletal muscle by nucleotide sequence analysis of isolate full-length cDNAs and authentication of their functional properties using the Xenopus oocyte expression system; 2) to determine the cellular and subcellular localization of the rat skeletal muscle sodium channel alpha subunits by immuno-cytochemical and ultra-structural techniques, using antibodies raised against unique portions of the alpha subunit peptides; 3) to determine the molecular basis of tetrodotoxin (TTX)-sensitivity and -insensitivity utilizing sodium channel mRNA analysis in TTX-sensitive adult muscle and relatively TTX-resistant embryonic and denervated muscle. In mammals, spontaneous mutations of sodium channel genes that overtly disturb normal nervous system and skeletal muscle function are anticipated to occur, based on the key role of the sodium channel in signalling and information-processing, and the large number of genes involved in sodium channel protein production in may tissues. These planned studies, in conjunction with my experience in genetics, will provide the framework for addressing the role of putative muscle sodium channel gene mutations in disease of skeletal muscle in man.