NEURONAL CALCIUM CHANNELS--REGULATION AND FUNCTION

神经元钙通道——调节和功能

• 批准号: 2714502
• 负责人: Diane Lipscombe
• 金额: $ 21.33万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-01 至 2001-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2714502
• 关键词: RNA splicing; RNase protection assay; Xenopus oocyte; calcium channel; laboratory rat; membrane potentials; molecular cloning; neurons; protein structure function; single cell analysis; sympathetic nervous system; voltage /patch clamp; voltage gated channel

This project is aimed at elucidating the regulation and functional role of voltage-gated calcium (Ca) channels in the peripheral nervous system of vertebrates. Voltage-gated Ca channels are essential for the normal function of the sympathetic nervous system. Ca ions, entering the neuron via voltage-gated channels that open in response to depolarizing stimuli, regulate a diverse spectrum of functions including neurotransmitter release, neurite outgrowth, neuronal excitability and gene expression. Several different types of Ca channels have been identified and each is likely to be specialized for regulating particular Ca-dependent processes. This proposal focuses on studying N and L type Ca channels of sympathetic neurons and on determining their relative importance in the control of neurosecretion and neuronal excitability. Single Ca channel currents will be recorded with the use of patch-clamp technique from sympathetic neurons isolated from adult rats and frogs. The behavior of N and L channels will be studied in high resolution single channel recordings in order to characterize the gating pattern of each component. A direct comparison of neurons from adult frog and rat will be essential in addressing possible species-based differences in the behavior of Ca channels. Receptor-mediated inhibition of Ca channel currents is important in pre-synaptic inhibition of transmitter release. The effect of norepinephrine (NE) on the gating of single Ca channel currents will be studied in detail to determine the mechanism of inhibition. The consequences of directly activating various second messenger systems proposed to be involved in transducing the effects of NE and other neurotransmitters on Ca channel function will also be determined. Neurotransmitter release in isolated sympathetic neurons will be monitored by measuring, in the same patch, both the changes in membrane capacitance and the properties of the resident Ca channel currents. This will be achieved with a modified version of the patch clamp recording technique. The location of specialized zones of transmitter release will be determined in cell-attached patches obtained from cell bodies, axons and growth cones of sympathetic neurons. The hypothesis that N channels cluster within specialized transmitter release zones will be tested by monitoring single Ca channel currents and capacitance changes in the same cell-attached patches. The functional role of different classes of Ca channels in activating two distinct Ca-activated K channel currents (KCa and KAHP) in sympathetic neurons will be determined. Cell-attached patches from various cellular regions will establish whether a particular type of Ca channel co-localizes with a specific Ca-activated K channel. A better appreciation of the inter-relationship between different classes of Ca and K channel currents will provide new insights into the mechanisms by which neuronal excitability and neurotransmitter release are regulated.

该项目旨在阐明调节和功能作用 电压门控钙（CA）通道 脊椎动物。 电压门控的CA通道对于正常 交感神经系统的功能。 Ca离子，进入神经元 通过响应去极化刺激的电压门控通道， 调节包括神经递质在内的各种功能 释放，神经突生长，神经元兴奋性和基因表达。 已经确定了几种不同类型的CA通道，每种通道 可能专门用于调节特定的CA依赖性过程。 该建议重点是研究n和l类型的同情渠道 神经元并确定其在控制中的相对重要性 神经分泌和神经元兴奋性。 单个CA通道电流将通过使用贴片钳记录 来自成年大鼠和青蛙分离的交感神经元的技术。 这 N和L通道的行为将以高分辨率单一研究 频道记录以表征每个频道的门控模式 成分。 对成年青蛙和大鼠神经元的直接比较将是 解决可能基于物种的行为差异至关重要 CA通道。 受体介导的CA通道电流的抑制是 在突触前抑制递质释放中很重要。 效果 单次CA通道电流门控的去甲肾上腺素（NE）将是 详细研究以确定抑制的机制。 这 直接激活各种第二会系统的后果 提议参与转导NE和其他其他的影响 CA通道功能上的神经递质也将得到确定。 将监测孤立的交感神经元中的神经递质释放 通过在同一斑块中测量膜电容的变化 以及居民CA通道电流的性质。 这将是 通过修改版的贴片夹录制技术实现。 将确定发射机释放的专业区域的位置 在从细胞体，轴突和生长锥获得的细胞附着斑块中 同情神经元。 n通道群集中的假设 专门的发射器释放区将通过监视单一测试 CA通道电流和电容变化在相同的细胞连接 补丁。 不同类别的CA通道在激活两个方面的功能作用 同情的独特的CA激活K通道电流（KCA和KAHP） 神经元将被确定。 来自各种细胞的细胞跟踪斑块 区域将确定特定类型的CA通道是否共定位 具有特定的CA激活K通道。 更好地欣赏 CA和K通道电流的不同类别的相互关系 将为神经元的机制提供新的见解 兴奋性和神经递质释放受到调节。