Dopamine D2 Receptor Splice Variants and Autoreceptor Function

多巴胺 D2 受体剪接变体和自身受体功能

• 批准号: 9241697
• 负责人: KIM Arthur NEVE
• 金额: --
• 依托单位: PORTLAND VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-10-01 至 2020-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9241697
• 关键词: Address; Agonist; Alternative Splicing; Autoreceptors; Basic Science; Behavior; Biological Models; Calcium; Calcium-Binding Proteins; Cell Line; Cocaine; Corpus striatum structure; Development; Diagnosis; Dopamine; Dopamine D2 Receptor; Dopamine Receptor; Drug Addiction; Drug Controls; Drug abuse; Drug usage; Electrophysiology (science); Exhibits; Family; Functional disorder; G-Protein-Coupled Receptors; G-substrate; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; Knock-out; Knockout Mice; Left; Mammalian Cell; Measures; Mediating; Membrane; Mental disorders; Midbrain structure; Military Personnel; Modeling; Motor Activity; Mus; Neurons; Organism; Parkinson Disease; Pathway interactions; Patients; Pharmacological Treatment; Phenotype; Population; Property; Proteins; RNA Splicing; Recombinants; Regulation; Resources; Rewards; Rodent; Schizophrenia; Signal Transduction; Taste aversion; Testing; United States; Update; Variant; Veterans; Virus; Wild Type Mouse; Work; base; behavior measurement; behavioral sensitization; desensitization; dopamine system; dopaminergic neuron; drug seeking behavior; induced pluripotent stem cell; insight; member; mutant; nervous system disorder; neurochemistry; neuropsychiatric disorder; postsynaptic; preference; presynaptic; receptor; reuptake; stimulant abuse; substance abuse treatment; therapeutic target

The five subtypes of dopamine receptors (D1-D5) are members of the superfamily of G protein-coupled receptors. The D1 and D2 subtypes are the most abundant and mediate most classic dopamine-dependent behaviors. This application is focused on the D2 receptor and, in particular, on the functional significance of a 29-residue fragment in the third cytoplasmic loop that is alternatively spliced to produce the short and long forms of the D2 receptor, D2S and D2L. Considerable evidence indicates that the D2 receptor is the primary autoreceptor that regulates DA neuron activity and DA release, and it is widely accepted that D2S is that autoreceptor, whereas D2L is the postsynaptic receptor expressed in striatal medium spiny neurons. In contrast, our work supports a model in which rodent dopamine neurons express both splice variants, and both function as autoreceptors with some subtle differences. We have determined that one difference between the splice variants is their rate of calcium-dependent desensitization and we now propose to evaluate the significance of this difference for cocaine-induced sensitization, reward, and aversion, while also comparing other functional properties of the splice variants. In the first specific aim we will compare additional aspects of the function of D2L and D2S as the presynaptic autoreceptor that inhibits dopamine release, dopamine neuron firing, and locomotor activity. We will use virus-mediated expression of D2L or D2S in the midbrain of D2 receptor null-mutant (D2-KO) mice and of mice with regional D2 receptor knock- out, to restore the expression of either D2L or D2S in dopamine neurons prior to assessing measures of D2 autoreceptor activity. We will also determine if both variants regulate G protein-mediated signaling in striatal neurons. This aim will focus on receptor localization and regulation of dopamine release and reuptake, and will explore the hypotheses that cocaine alters the distribution or expression of the variants. The second specific aim is based on alternative hypotheses that a cocaine-induced somatodendritic autoreceptor switch from D2S to D2L triggers or reflects other changes that produce behavioral sensitization, conditioned place preference to cocaine, and decreased aversion, or that the phenotype switch is a compensatory mechanism that mediates decreased reward and increased aversion. In this aim we will test these hypotheses by measuring cocaine-induced behavioral sensitization, conditioned place preference, and conditioned taste aversion in mice expressing only D2S or D2L autoreceptors. Experimental support for either hypothesis will provide valuable insight into the relevance of D2 receptor alternative splicing for DA neuron function.

多巴胺受体的五个亚型（D1-D5）是G蛋白偶联的超家族的成员 受体。 D1和D2亚型是最丰富，最经典的多巴胺依赖性的 行为。该应用集中在D2受体上，尤其是在功能意义上 第三个细胞质环中的29个残基片段，替代剪接以产生短而长的片段 D2受体，D2S和D2L的形式。大量证据表明D2受体是主要的 调节DA神经元活动和DA释放的自身受体，并且广泛认为D2是 自身受体，而D2L是在纹状体培养基神经元中表达的突触后受体。在 对比，我们的工作支持一个模型，其中啮齿动物多巴胺神经元表达剪接变体，并且 两者都充当具有一些细微差异的自身受体。我们已经确定一个差异 剪接变体之间是它们依赖钙依赖性脱敏的速率，我们现在建议 评估这种差异对可卡因引起的致敏，奖励和厌恶的重要性，而 还比较剪接变体的其他功能特性。在第一个特定目标中，我们将比较 D2L和D2S作为抑制多巴胺的突触前自身受体的功能的其他方面 释放，多巴胺神经元发射和运动活性。我们将使用病毒介导的D2L或 D2受体无效（D2-KO）小鼠中脑中的D2S和具有区域D2受体敲门的小鼠 在评估D2的测量之前，要恢复多巴胺神经元中D2L或D2的表达 自身受体活动。我们还将确定两个变体是否调节纹状体中G蛋白介导的信号传导 神经元。该目标将重点放在受体定位和多巴胺释放和再摄取的调节，以及 将探讨可卡因改变变体的分布或表达的假设。第二个 具体目的是基于可卡因诱导的体育体自身受体的替代假设 从D2S切换到D2L触发器或反映了产生行为敏化的其他变化，条件 优先选择可卡因，减少厌恶，或者表型开关是补偿性的 介导的机制减少了奖励和增加的厌恶。在此目标中，我们将测试这些 通过测量可卡因诱导的行为敏化，条件的位置偏好和 仅表达D2S或D2L自身受体的小鼠中的条件味道厌恶。实验支持 任何一个假设都将提供有关D2受体替代剪接与DA的相关性的宝贵见解 神经元功能。