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: 8616404
• 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 2015-08-23
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8616404
• 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（由适用提供）：杏仁核和海马的功能障碍会引起焦虑症。各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）来调节这些大脑区域。 GI/OPCR抑制突触前CAV2.2通道，该通道在海马和杏仁核中控制发射机在兴奋性和抑制突触时释放。因此，该项目的假设是GI/OPCR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有关的神经元回路的分子生物学，行为和突触物理学。该项目的具体目的是：a）确定是否减少 GI/OPCR耦合到CAV2.2通道会影响海马突触中的神经递质释放。 Lipscombe实验室表明，在CAV2.2基因中消除外显子37a会降低通道对GI/OPCR抑制的敏感性。为了建立合成作用，我们产生了缺乏外显子37a的小鼠。我们的初始数据显示，与WT相比，在培养基的培养基途径道齿中的配对脉冲比较低，这表明通过降低Cav2.2通道的GI/OPCR抑制产生的神经递质释放增加。在此目标中，我将进一步分析GI/OPCR和CAV2.2之间缺乏耦合对海马中神经递质释放的影响。 b）确定GI/OPCR耦合与CAV2.2通道的破坏是否会影响与动画相关的行为。在我们的最初研究中，与野生型相比，E37a占用的小鼠暴露于新颖性诱导的低迷型肌张力，这表明gi/opcr抑制作用的降低对CAV2.2通道的降低会降低动画水平。我将使用空旷的零迷宫扩展并确认这些令人兴奋的结果。 c）确定在焦虑状态下，通过gi/opcr抑制Cav2.2通道对基底外侧杏仁核的GABA能突触是否进行了更新。先前的报道将动画与基底外侧杏仁核中GABA能传播的减少有关。大多数研究在焦虑症中以突触后的变化进行了记录，但是关于发射器释放的突触前控制鲜为人知。在此目标中，我将确定在焦虑状态下杏仁核中依赖CAV2.2依赖性的GABA释放。 d）在对抗焦虑药的耐受性期间，调节​​了gi/opcr激动剂对谷氨酸能突触的抑制作用。使用耐受性的小鼠模型，我将测量敏感性CAV2.2通道对NA¿VE中的外源激动剂介导的GI/OPCR抑制作用，并在谷氨酸能传播中进行药物处理的小鼠。