ELECTROPHYSIOLOGY OF THE PI-PKC SYSTEM IN HIPPOCAMPUS

海马 PI-PKC 系统的电生理学

• 批准号: 2264347
• 负责人: BRADLEY E ALGER
• 金额: $ 15.86万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-04-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2264347
• 关键词: NMDA receptors; adenosine triphosphate; brain electrical activity; calcium channel; calcium flux; enzyme activity; excitatory aminoacid; flash photolysis; glutamates; guanosine triphosphate; guinea pigs; hippocampus; laboratory rat; neurons; phosphatase inhibitor; phosphatidylinositols; phosphoprotein phosphatase; protein kinase C; second messengers; tissue /cell culture; voltage /patch clamp; voltage gated channel

The phosphatidylinositol-protein-kinase-C (PI-PKC) system is a ubiquitous second messenger system in the central nervous system. However, in contrast to the depth at which it is understood at the biochemical and molecular biological levels, there is still a paucity of information regarding its neurophysiological functions at the cellular and molecular levels. Glutamate, PKC, voltage-dependent Ca2+ channels (VDCCs) and Ca2+- dependent K+ after hyperpolarizations have all been implicated in a model of the establishment of memory traces, long-term potentiation (LTP), and in epileptic and neurodegenerative phenomena. The highest concentrations of PKC are found in the hippocampus, in which both the physiological and pathological events are known to occur. The ultimate goal of this project is to understand the role of the neurotransmitter-activated PI-PKC system in the control of neuronal excitability using state-of-the-art electrophysiological techniques in several in vitro hippocampal neuron preparations: slices, tissue-culture and acute isolation. The interrelationships among glutamate, PKC, VDCCs and the AHP have not bee clarified. This project seeks to provide this clarification using whole- cell voltage clamp and patch clamp techniques, at two levels: the nature of the second messenger control exerted by glutamate and the regulation of VDCCs and AHP channels by PKC. Investigation of these general issues will take place by testing specific hypotheses that have been developed from past work on this project. The hypotheses are: 1) that high-voltage- activated hippocampal Ca2+ channels are regulated by the action of a complementary kinase-phosphatase system involving PKC and a protein phosphatase, 2) that glutamate depresses Ca2+ currents via PKC activation and 3) that the hippocampal AHP current is regulated by PKC at the level of the single AHP channel. These hypotheses make explicit predictions and are susceptible to clear tests with voltage- and patch-clamp methods. The outcome of these tests will provide valuable information as to the functional role of the PI-PKC system, and, since ion channels and neurotransmitters to be studied have been implicated in a variety of neurological disease states, particularly epilepsy, to the understanding of, and ability to influence, these conditions as well.

磷脂酰肌醇 - 蛋白 - 激酶-C（PI-PKC）系统无处不在 中枢神经系统中的第二信使系统。 但是，在 与生化的深度形成对比 分子生物学水平，信息仍然很少 关于其在细胞和分子的神经生理功能 水平。 谷氨酸，PKC，电压依赖性Ca2+通道（VDCC）和Ca2+ - 超极化后依赖的K+都与模型有关 建立记忆痕迹，长期增强（LTP）和 在癫痫和神经退行性现象中。 最高浓度 PKC的海马在生理和 已知发生病理事件。 该项目的最终目标 是要了解神经递质激活的PI-PKC系统的作用 在控制神经元的兴奋性中 几种体外海马神经元中的电生理技术 制剂：切片，组织文化和急性分离。 谷氨酸，PKC，VDCC和AHP之间的相互关系没有蜜蜂 澄清。 该项目旨在使用整个 细胞电压夹和斑块夹技术，分为两个级别：性质 由谷氨酸施加的第二个信使控制和调节 PKC的VDCC和AHP频道。 对这些一般问题的调查将 通过测试从 过去在这个项目上工作。 假设是：1）高压 - 活化的海马Ca2+通道受A的作用调节 涉及PKC和蛋白质的互补激酶 - 磷酸酶系统 磷酸酶，2）谷氨酸通过PKC激活降低Ca2+电流 3）海马AHP电流受PKC的调节水平 单个AHP频道。 这些假设是明确的预测，并且容易明确 用电压和贴片钳方法进行测试。 这些测试的结果 将提供有关PI-PKC功能作用的宝贵信息 系统，并且由于要研究的离子通道和神经递质 与多种神经系统疾病状态有关 癫痫，对这些的理解和影响能力 条件也是如此。