MODULATION AND REGULATION OF NEURONAL CALCIUM CHANNELS

这个项目的目标是检查再生钙 在组织培养中生长的中枢神经系统神经元的电流和 儿茶酚胺对这些电流的影响。 钙依赖性作用 已经在中枢和外周脊椎动物中证明了潜力 神经元在过去的几年里。 在软体动物的神经细胞，心脏组织， 周围神经系统，一些儿茶酚胺已被发现， 通过改变钙通道的电压依赖性来起作用。 考虑到儿茶酚胺对正常大脑功能的重要性， 暗示了多种神经和精神疾病， 关键是要确定这些发射机的作用机制。 几 实验室已经表明，在脊椎动物神经元中， 电势可以优先位于枝晶上。 最近我们 证明了在二尖瓣细胞的钙峰的存在， 嗅球 这些细胞是一个有利的系统，用于研究 钙电流及其调节，因为1）它们可以维持在 分散的细胞组织培养，2）它们有长的树突， 参与相互突触，3）灯泡包含许多定义 单胺能细胞和终末的群体。 的神经元 在本研究中将使用幼鼠的嗅球。 电生理学研究将分两个阶段进行。 在第一个， 将用单个微电极穿透神经元， 将确定钙依赖性动作电位的特征。 然后将儿茶酚胺添加到浴中和/或直接离子电渗 对细胞的影响，对钙依赖性动作电位的影响将是 记录（例如上升率、持续时间、振幅）。 在第二阶段， 新开发的电压钳位技术的切除补丁， 膜将被用来研究钙的动力学性质， 当前在单个或多个通道级别上的详细信息。 然后它将 有可能研究这种电流的调制由儿茶酚胺在一个 比迄今为止所能达到的更基本的水平。

The goal of this project is the examination of regenerative calcium currents in central nervous system neurons grown in tissue culture and the effects of catecholamines on these currents. Calcium-dependent action potentials have been demonstrated in both central and peripheral vertebrate neurons in the last few years. In molluscan nerve cells, heart tissue, and peripheral nervous systems, some of the catecholamines have been found to act by modifying the voltage dependent properties of the calcium channel. Given the importance of catecholamines to normal brain function and their implication in a variety of neurologic and psychiatric disorders, it is critical to define the mechanism of action of these transmitters. Several laboratories have suggested that in vertebrate neurons calcium action potentials may be preferentially located on dendrites. Recently we have demonstrated the presence of calcium spikes in mitral cells of the olfactory bulb. These cells are a favorable system for the study of calcium currents and their modulation since 1) they can be maintained in dispersed cell tissue culture, 2) they have long dendrites which participate in reciprocal synapses, and 3) the bulb contains many defined populations of monoaminergic cells and terminals. Neurons from the olfactory bulb of young rats will be used in this study. Electrophysiological studies will proceed in two phases. In the first, neurons will be penetrated with a single microeletrode and the presence and characteristics of calcium dependent action potentials will be determined. Catecholamines will then be added to the bath an/or iontophoresed directly on the cells, and effects on the calcium dependent action potential will be noted (e.g. rate of rise, duration, amplitude). In the second phase, the newly developed technique of voltage clamping of excised patches of membranes will be used to study the kinetic properties of the calcium current in detail at a single or multiple channel level. It will then be possible to study the modulation of this current by catecholamines at a more basic level than has so far been possible.