Plasticity N-Type Ca2+ Channels in Sympathetic Neurons

交感神经元中的可塑性 N 型 Ca2 通道

基本信息

批准号：
6921882
负责人：
Ann R. Rittenhouse
金额：
$ 27.83万
依托单位：
UNIV OF MASSACHUSETTS MED SCH WORCESTER
依托单位国家：
美国
项目类别：
财政年份：
1995
资助国家：
美国
起止时间：
1995-06-01 至 2006-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6921882
关键词：
G protein arachidonate calcium channel laboratory rat neural plasticity neurotransmitters phosphorylation protein kinase C protein structure function sympathetic ganglion

项目摘要

DESCRIPTION (provided by applicant): The long-term goal of this lab is to identify sources of plasticity at the level of single proteins. Our working definition of plasticity at this level is the ability of a protein's behavior to vary, not simply due to an increase or decrease in its activity as with acute activation of an enzyme, but rather by qualitative changes in its behavior. Single N-type Ca channels display heterogeneous activity, called modes, where unitary conductance and kinetics are stable for seconds to minutes before abruptly changing to a new pattern of activity. Because the transitions among modes result in qualitative changes in N-type Ca channel activity, they can be considered plastic proteins. The N-type calcium (Ca) channel is found only in nerve cells and neuronally-derived tissues. It is the most extensively modulated Ca channel in the brain in that more pathways exist for its modulation than for any other, and because of this, it is thought to play a critical role in synaptic plasticity. The proposed experiments test the hypothesis that transmitters exert their actions on N-type Ca channels by activating signaling molecules that shift channel activity from one mode to another. The specific aims of this project are the following: 1) confirm that phosphorylation of the N-type Ca channel by protein kinase C (PKC) stabilizes an inactivating mode with long openings; 2) determine whether G-proteins protect channels from inactivation; 3) determine whether arachidonic acid (AA)-induced inhibition stabilizes a null activity mode; 4) demonstrate that transmitters, use PKC and AA to modulate N-type currents. Whole cell and unitary N-type currents will be studied with standard patch clamp techniques in superior cervical ganglion neurons, a preparation rich in N-type Ca channels. The effects of signaling molecules on current amplitude, gating kinetics, and rates of transition between different modes will be analyzed quantitatively. We expect to find that transmitters do converge on these signaling molecules to modulate Ca currents by stabilizing particular modes. If true, plasticity of N-type Ca channels may be a building block for emergent forms of plasticity, observed at synapses and in neural circuits. Moreover, these results should establish new signal transduction cascades for N-type Ca channel modulation, which may also be present in central neurons. Further understanding of the modulation of N-type Ca channel modes might allow the design of new pharmaceutical agents that act to stabilize modes which alter net Ca influx. This could help minimize cytotoxicity that can occur during cerebral vasospasm, stroke, epilepsy; and reduce mobility from cognitive, and/or learning and memory disorders.

描述（由申请人提供）：该实验室的长期目标是确定单一蛋白质水平的可塑性来源。我们的工作此级别可塑性的定义是蛋白质行为的能力变化，不仅仅是由于其活性的增加或减少酶的急性激活，而是通过其质的变化行为。单个 N 型 Ca 通道表现出异质活性，称为模式，其中单一电导和动力学稳定几秒到几分钟在突然改变为新的活动模式之前。因为过渡模式之间导致 N 型 Ca 通道活性发生质的变化，它们可以被认为是塑料蛋白。发现 N 型钙 (Ca) 通道仅存在于神经细胞和神经元衍生组织中。它是最广泛的调节大脑中的 Ca 通道，因为存在更多的途径调制比任何其他调制都重要，正因为如此，它被认为可以发挥在突触可塑性中发挥关键作用。所提出的实验测试了假设递质通过 N 型 Ca 通道发挥作用激活信号分子，将通道活动从一种模式转变为其他。该项目的具体目标如下： 1）确认蛋白激酶 C (PKC) 对 N 型 Ca 通道的磷酸化稳定具有长开口的失活模式； 2) 判断是否有G蛋白保护通道免于失活； 3) 判断是否含有花生四烯酸 (AA) 诱导的抑制稳定无效活性模式； 4）证明发射机，使用PKC和AA来调制N型电流。全细胞和将使用标准膜片钳技术来研究单一 N 型电流颈上神经节神经元，富含 N 型 Ca 通道的制剂。信号分子对电流幅度、门控动力学和不同模式之间的转换率将进行定量分析。我们期望发现发射器确实会聚在这些信号分子上通过稳定特定模式来调节 Ca 电流。如果为真，则可塑性为 N 型 Ca 通道可能是新兴可塑性形式的基础，在突触和神经回路中观察到。此外，这些结果应该为 N 型 Ca 通道调制建立新的信号转导级联，它也可能存在于中枢神经元中。进一步了解 N 型 Ca 通道模式的调制可能允许设计新的作用于稳定改变净 Ca 流入的模式的药剂。这可能有助于最大限度地减少脑血管痉挛期间可能发生的细胞毒性，中风，癫痫；并减少认知和/或学习的流动性和记忆障碍。