CALCIUM SIGNALING IN NERVE CELLS

神经细胞中的钙信号传导

• 批准号: 2268631
• 负责人: SIMON LEVY
• 金额: $ 13.74万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-04-10 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2268631
• 关键词: calcium binding protein; calcium flux; calcium indicator; carbohydrate receptor; heparin; horseshoe crabs; inositol phosphates; membrane channels; membrane permeability; microelectrodes; microinjections; neuropharmacology; visual photoreceptor; voltage /patch clamp

In many nerve cells, transient increases in intracellular free calcium concentrations (Caj) are caused primarily by influx through voltage- dependent Ca channels. Second messengers like inositol triphosphate (InsP3) also have the ability to increase Caj) through release from intracellular stores, or gating of calcium channels. The long-term goal of this research is to investigate mechanisms by which second messengers such as Ca2+ or InsP3 modulate the excitability of nerve cells by controlling their membrane permeability. We have developed suitable technologies: 1) to measure single-channel activities ii) to simultaneously measure changes in intracellular Ca and membrane currents; iii) to pressure-inject pharmacological agents to investigate putative pathways involved in neuronal excitability. There are three specific aims of the proposed research. 1. We will test the hypothesis that InsP3 directly activates ion channels in the plasma membrane of isolated nerve cells by recording single-channels gated by InsP3 in excised patches. We will determine properties of the excise patch by: 1) puffing different concentrations of InsP3. ii) comparing InsP3 or InsP4 on the same patch. iii) puffing InsP3 with different concentration of Ca2+. iv) puffing InsP3 with heparin. 2. We will determine whether the Cai increase resulting from Ca influx is potentiated by release of calcium form intracellular stores by injecting heparin or applying thapsigargin, agents that inhibit the action of InsP3 or induce depletion of intracellular stores. Intracellular calcium will be measured with Ca-sensitive electrodes. 3. We will directly test the hypothesis that the inability of InsP3 to release additional Ca2+ from internal stores following a prior mobilization of Ca2+ is due to a lingering elevation of Cai and the presence of an additional factor present only in certain areas of the cell. We will determine the threshold of desensitization of InsP3 injections by injecting increasing amounts of calcium. We will simultaneously measure Cai with aequorin and Ca-sensitive electrodes. The combination of these electrophysiological and pharmacological techniques should prove useful in gathering new and important information about nerve cell function. In particular, the studies on the long lasting afterdischarge in nerve cells, may contribute to a better understanding of the long lasting hyperexcitability of human brain cells in epilepsy.

在许多神经细胞中，细胞内无钙的瞬时增加 浓度（CAJ）主要是由电压涌入 依赖的CA通道。 第二个使者，例如三磷酸肌醇 （insp3）还具有增加caj的能力）通过释放 细胞内存储或钙通道的门控。 长期目标 这项研究的是研究第二使者的机制 例如CA2+或INSP3来调节神经细胞的兴奋性 控制其膜渗透性。 我们已经开发了合适​​的技术：1）测量单通道 活动ii）同时测量细胞内CA的变化和 膜电流； iii）到压力注射药理学剂到 研究参与神经元兴奋性的推定途径。 拟议的研究有三个具体目标。 1。我们将测试INSP3直接激活离子的假设 通过记录孤立神经细胞的质膜中的通道 单渠道由INSP3在切除的贴片中门控。 我们将确定 消费池的特性通过：1）膨化不同的浓度 insp3。 ii）在同一补丁上比较INSP3或INSP4。 iii）浮肿 INSP3具有不同浓度的Ca2+。 iv）用 肝素。 2。我们将确定CA I增加是否由CA涌入产生 通过释放钙形成细胞内存储的增强 注射肝素或施用thapsigargin，抑制的剂 INSP3的作用或诱导细胞内存储的消耗。 细胞内钙将用CA敏感电极测量。 3。我们将直接检验以下假设： 在先验之后从内部商店释放其他CA2+ CA2+的动员是由于CAI的挥之不去的升高和 仅存在附加因素 细胞。 我们将确定insp3脱敏的阈值 通过注射增加的钙来注射。 我们将 同时用Aquorin和CA敏感电极测量CAI。 这些电生理学和药理的组合 技术应被证明可用于收集新的重要信息 关于神经细胞功能。 特别是关于长期的研究 神经细胞中持久的后递送，可能有助于更好 了解人脑细胞持久的过度持续性 在癫痫中。