MOLECULAR MECHANISMS OF GATING IN IONIC CHANNELS

离子通道门控的分子机制

• 批准号: 3278140
• 负责人: WOLFGANG F NONNER
• 金额: $ 15.69万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1981
• 资助国家: 美国
• 起止时间: 1981-08-01 至 1988-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3278140
• 关键词: adenosine triphosphate; cyclic AMP; dorsal root; electrophysiology; hippocampus; membrane permeability; membrane potentials; myofibrils; spinal ganglion; tissue /cell culture

It is proposed to study molecular aspects of gating and regulatory processes in voltage-dependent Na and K ion channels of rat myoballs, dorsal root ganglion cells and hippocampal neurons. The cells will be maintained in primary tissue culture. The patch clamp technique will be used to record from whole cell membranes and from small membrane patches containing only a few ion channels. For testing whether inactivation of Na channels is kinetically linked to their activation, small ensembles of Na channels will be stimulated with voltage protocols designed to test for effects of channel opening on the rate of channel inactivation. We will examine whether the opening/closing step of activation gating is slow with regard to other activation steps, as might be expected if channel opening involves a major change in configuration. The latter single-channel measurements will be done on Na channels whose inactivation has been chemically blocked or slowed. Inactivating and non-inactivating forms of K channel will be characterized at the single channel level; microscopic aspects of their gating kinetics will be compared to those found for Na channels. Regulatory effects of maintained membrane voltages will be examined in individual Na and K channels. Various ions (to be used for intracellular solutions), as well as chemicals with possible regulatory effects (cAMP, ATP, and thiamine derivatives) will be introduced into cells and their possible effects on the function of Na and K channels will be characterized. Conditions essential for survival of channels in excised membrane patches will be explored. We will test whether Na and K channels of our preparations, like K channels of myelinated nerve, undergo spontaneous changes of gating behaviour. The long range goal is to understand how Na and K channels in excitable membranes are controlled by changes of the membrane potential and, in the long term, by modulatory processes.

建议研究门控和调节的分子方面 大鼠Myoballs的电压依赖性Na和K离子通道中的过程， 背根神经节细胞和海马神经元。 细胞将是 维持在原发性组织培养物中。 贴片夹技术将是 用于从整个细胞膜和小膜斑记录 仅包含几个离子通道。 用于测试NA的失活是否 通道在动力学上与它们的激活相关 通道将通过旨在测试的电压协议来刺激 通道打开对通道失活率的影响。 我们将 检查激活门控的开放/结束步骤是否很慢。 关于其他激活步骤 涉及配置的重大变化。 后者的单渠道 测量将在灭活已有的NA通道上进行 化学阻塞或放慢速度。 K的灭活和非活活形式的K 通道将在单个通道级别进行表征；显微镜 将其门控动力学的各个方面与NA的那些方面进行比较 频道。 维持膜电压的调节作用将是 在单个NA和K频道中检查。 各种离子（用于 细胞内溶液）以及可能调节的化学物质 效果（CAMP，ATP和硫胺素衍生物）将被引入细胞 它们对Na和K频道功能的可能影响将是 特征。 切除通道生存至关重要的条件 将探索膜贴片。 我们将测试NA和K频道是否 我们的准备工作，例如骨髓神经的K频道 门控行为的自发变化。 远程目标是 了解如何控制可激发膜中的Na和K频道 膜电位的变化以及长期通过调节的变化 过程。