MODULATION AND REGULATION OF NEURONAL CALCIUM CHANNELS

该项目的目标是检测再生钙。 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。钙依赖作用 在中枢和外周脊椎动物中都显示出潜力 神经元在过去的几年里。在软体动物神经细胞、心脏组织和 外周神经系统，一些儿茶酚胺已被发现 通过改变钙通道的电压依赖属性来起作用。 鉴于儿茶酚胺对正常大脑功能的重要性以及它们 与各种神经学和精神障碍有关，它是 对确定这些发射器的作用机制至关重要。几个 实验室已经表明，在脊椎动物的神经元中，钙的作用 电位可能优先位于树枝晶上。最近我们有 证实二尖瓣细胞中存在钙尖峰。 嗅球。这些细胞是一个良好的研究系统。 钙电流及其调节，因为1)钙电流可以维持在 分散的细胞组织培养；2)有较长的树枝状突起 参与相互突触，3)球状突触包含许多已定义的 单胺能细胞和终末的群体。来自大脑的神经元 这项研究将使用幼年大鼠的嗅球。 电生理学研究将分两个阶段进行。首先， 神经元将被单个微电极穿透，并且存在和 钙依赖动作电位的特性将被确定。 然后将儿茶酚胺加入浴缸和/或直接离子漂浮。 对细胞的影响，以及对钙依赖动作电位的影响 注意(例如，上升速度、持续时间、幅度)。在第二阶段， 新开发的切除贴片的电压钳制技术 膜将被用来研究钙的动力学性质 详细描述了单通道或多通道级别的电流。那么它将会是 可以研究儿茶酚胺对这一电流的调制 比到目前为止更基本的水平。

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.