Role of Gi/o-Protein Inhibition of CaV2.2 Channels in Anxiety Behavior

CaV2.2 通道的 Gi/o 蛋白抑制在焦虑行为中的作用

• 批准号: 8423866
• 负责人: Arturo Andrade
• 金额: $ 9万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-08 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8423866
• 关键词: Affect; Agonist; Amygdaloid structure; Anti-Anxiety Agents; Anxiety; Anxiety Disorders; Area; Bathing; Behavior; Behavioral; Biological; Brain; Collaborations; Conotoxin; Coupling; Data; Dependency; Drug Targeting; Electrophysiology (science); Excitatory Postsynaptic Potentials; Excitatory Synapse; Exhibits; Exons; Functional disorder; G Protein-Coupled Receptor Genes; Genes; Glutamates; Hippocampus (Brain); Inhibitory Synapse; Interneurons; Knockout Mice; Link; Measures; Medial; Mediating; Methods; Molecular; Molecular Biology; Monitor; Mus; Neurons; Neurotransmitters; Opioid; P-Q type voltage-dependent calcium channel; Perforant Pathway; Pharmaceutical Preparations; Phase; Physiologic pulse; Probability; Protein Inhibition; Proteins; RNA Splicing; Relative (related person); Reporting; Research; Research Personnel; Role; Slice; Synapses; Testing; Time; dentate gyrus; effective therapy; feeding; gamma-Aminobutyric Acid; mouse model; neurotransmission; neurotransmitter release; novel; postsynaptic; presynaptic; programs; public health relevance; receptor coupling; skills; transmission process

DESCRIPTION (provided by applicant): Dysfunction of the amygdala and hippocampus can cause anxiety disorders. Various neurotransmitters and drugs with anxiolytic effects modulate these brain areas by activating Gi/o protein coupled receptors (Gi/oPCRs). Gi/oPCRs inhibit presynaptic CaV2.2 channels, which control transmitter release at excitatory and inhibitory synapses in the hippocampus and amygdala. Therefore, the hypothesis of this project is that activation of Gi/oPCRs inhibits presynaptic CaV2.2 channels and reduces anxiety levels. My research plan combines molecular biology, behavior and synaptic electrophysiology of neuronal circuits related to anxiety. The specific aims of this project are: a) To determine if reduction of Gi/oPCR coupling to CaV2.2 channels impacts neurotransmitter release in hippocampal synapses. The Lipscombe lab showed that elimination of exon 37a in the CaV2.2 gene decreases channel sensitivity to Gi/oPCR inhibition. To establish a synaptic role, we generated a mouse that lacks exon 37a. Our initial data showed a lower paired-pulse ratio in the medial perforant path- dentate gyrus of 37a-lacking mice compared to WT, suggesting an increase in neurotransmitter release produced by a reduction of Gi/oPCR inhibition of CaV2.2 channels. In this aim, I will further analyze the effect of the lack of coupling between Gi/oPCRs and CaV2.2 on the neurotransmitter release in hippocampus. b) To determine if the disruption of Gi/oPCR coupling to CaV2.2 channels affect anxiety-related behavior. In our initial studies, e37a-lacking mice exhibited shorter latency times to feed in novelty-induced hypophagia compared to wild-type, suggesting that reduction of Gi/oPCR inhibitory action on CaV2.2 channels lowers anxiety levels. I will extend and confirm these exciting results using open field and elevated zero maze. c) To determine if the inhibition of CaV2.2 channels by Gi/oPCR on gabaergic synapses of basolateral amygdala is upregulated during anxiety states. Previous reports have associated anxiety to a reduction in gabaergic transmission in basolateral amygdala. Most studies have documented changes postsynaptically during anxiety but surprisingly little is known about presynaptic control of transmitter release. In this aim, I will determine whether CaV2.2-dependent GABA release is reduced in the amygdala during anxiety states. d) To determine if the inhibition of CaV2.2 channels by Gi/oPCR agonists on glutamatergic synapses is down regulated during tolerance to anxiolytics. Using mouse models of tolerance, I will measure the sensitivity CaV2.2 channels to Gi/oPCR inhibition mediated by exogenous agonists in na¿ve and drug-treated mice in glutamatergic transmission.

描述（由申请人提供）：杏仁核和海马体的功能障碍可引起焦虑症。多种神经递质和具有抗焦虑作用的药物通过激活 Gi/o 蛋白偶联受体 (Gi/oPCR) 抑制突触前 CaV2 来调节这些大脑区域。 2 个通道，控制海马体兴奋性和抑制性突触的递质释放因此，这个项目的假设是Gi/oPCRs的激活抑制突触前CaV2.2通道并降低焦虑水平，我的研究计划结合了与焦虑相关的神经元回路的分子生物学、行为学和突触电生理学。项目是： a) 确定是否减少 Gi/oPCR 与 CaV2.2 通道的耦合会影响海马突触中的神经递质释放。 Lipscombe 实验室表明，消除 CaV2.2 基因中的外显子 37a 会降低通道对 Gi/oPCR 抑制的敏感性。我们的初始数据显示，内侧穿通齿状回的配对脉冲比较低。与 WT 相比，缺乏 37a 的小鼠表明 CaV2.2 通道的 Gi/oPCR 抑制减少而导致神经递质释放增加。在这个目标中，我将进一步分析 Gi/oPCR 和 CaV2 之间缺乏耦合的影响。 .2 对海马神经递质释放的影响 b) 确定 Gi/oPCR 与 CaV2.2 通道耦合的破坏是否会影响焦虑相关行为。与野生型相比，小鼠在新奇引起的吞咽不足中进食的潜伏时间更短，这表明 Gi/oPCR 对 CaV2.2 通道的抑制作用的减少可以降低焦虑水平，我将使用开放场和高架零迷宫扩展并证实这些令人兴奋的结果。 c) 确定 Gi/oPCR 对基底外侧杏仁核 gabaergic 突触的 CaV2.2 通道抑制是否在焦虑状态下上调。大多数研究都记录了焦虑期间突触后的变化，但令人惊讶的是，我们对突触前递质释放的控制知之甚少。为此，我将确定焦虑状态期间杏仁核中 CaV2.2 依赖性 GABA 释放是否减少。 d) 确定 Gi/oPCR 激动剂对谷氨酸突触的 CaV2.2 通道抑制在耐受期间是否下调使用抗焦虑药的小鼠模型，我将测量 CaV2.2 通道对外源性激动剂介导的 Gi/oPCR 抑制的敏感性。和药物治疗的小鼠的谷氨酸能传递。