ION CHANNELS IN MUSCLE

肌肉中的离子通道

• 批准号: 3412387
• 负责人: JOHN H CALDWELL
• 金额: $ 15.32万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-08-01 至 1994-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3412387
• 关键词: Anura; acetylcholine; autoradiography; calcium; chloride channels; cyclic nucleoside monophosphate; electrophysiology; extracellular matrix; fresh water environment; immunocytochemistry; in situ hybridization; laboratory rat; membrane channels; membrane proteins; messenger RNA; muscle cells; nicotinic receptors; nontherapeutic iontophoresis; potassium channel; protein biosynthesis; saltwater environment; sodium channel; striated muscles; voltage /patch clamp

A multidisciplinary approach will be used to determine the distribution of ion channels in skeletal muscle ad to study mechanisms for creating, controlling, and maintaining these channel distributions. The density of channels along the length of the cell will be determined with new electrophysiological methods. The site of synthesis of the channels will be determined with in situ hybridization and immunocytochemistry. The enhanced spatial resolution of these electrical and histological techniques is revealing a complex ordering of ion channels. Ion channels are particularly important regulators of excitability in neurons and skeletal muscle. How the control of synthesis and localization of channels and other membrane proteins is accomplished is a fundamental question for all cells. The distribution and single channel properties of voltage-gated sodium channels will be studied with loose patch and tight patch voltage clamp. A new technique which combines both patch voltage clamp and ionophoresis will be used to find the degree of colocalization of sodium channels and acetylcholine receptors. Different distributions of sodium channels in fast and slow muscle may suggest functional roles for these channel distributions. Potassium channel and chloride channel distributions will be studied with the same techniques since there is evidence that these too are nonuniformly distributed in muscle. The pertinence of extending these studies to other channels is that the channels are not regulated in unison either spatially or in response to perturbations. thus it may be possible to identify both general and specific regulatory controls. The control of channel distribution could occur at any of a number of steps. Since skeletal muscle cells are multinucleated, it is possible that nuclei within the same cytoplasm are differentially regulated. This will be studied with in situ hybridization to determine the abundance and location of mRNA for the sodium channel and acetylcholine receptor. Labeled antibodies and snake toxin will be used to follow protein synthesis of these channels. Extracellular and intracellular factors that may regulate channel synthesis, distribution, or immobilization will be tested. These studies will also be done another multinucleated cell, the eel electrocyte, which also segregates membrane proteins (sodium channels, acetylcholine receptors, and sodium-potassium pumps).

将使用多学科方法来确定分布 骨骼肌中的离子通道研究创建的机制， 控制和维护这些渠道分配。 密度 沿单元长度的通道数将由新的确定 电生理学方法。 通道合成位点 将通过原位杂交和免疫细胞化学来确定。 这些电学和组织学的空间分辨率增强 技术揭示了离子通道的复杂排序。 离子 通道是兴奋性特别重要的调节者 神经元和骨骼肌。 如何控制合成 通道和其他膜蛋白的定位完成是 所有细胞的一个基本问题。 电压门控钠的分布和单通道特性 将使用松贴片和紧贴片电压钳来研究通道。 结合贴片电压钳和离子导入的新技术 将用于查找钠通道的共定位程度和 乙酰胆碱受体。 钠通道的不同分布 快肌和慢肌可能表明这些通道的功能作用 分布。 钾通道和氯通道分布 将使用相同的技术进行研究，因为有证据表明 这些在肌肉中的分布也是不均匀的。 的相关性 将这些研究扩展到其他渠道的原因是这些渠道不是 在空间上或响应扰动时一致调节。 因此，有可能确定一般性和具体性监管 控制。 渠道分配的控制可以发生在多个渠道中的任何一个 步骤。 由于骨骼肌细胞是多核的，因此有可能 同一细胞质内的细胞核受到不同的调节。 这将通过原位杂交进行研究以确定 钠通道和乙酰胆碱 mRNA 的丰度和位置 受体。 标记抗体和蛇毒素将用于后续 这些通道的蛋白质合成。细胞外和细胞内 可能调节渠道合成、分配或的因素 将测试固定性。 这些研究也将在另一次进行 多核细胞，鳗鱼电细胞，也分离膜 蛋白质（钠通道、乙酰胆碱受体和钠钾 泵）。