Regulation of striatal microcircuits by endogenous opioids as a novel mechanism underlying cocaine seeking

内源性阿片类药物对纹状体微电路的调节作为可卡因寻求的新机制

• 批准号: 10665060
• 负责人: Lauren K Dobbs
• 金额: $ 46.45万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10665060
• 关键词: Action Potentials; Affect; Attenuated; Automobile Driving; Axon; Behavior; Cells; Cocaine; Cocaine Abuse; Corpus striatum structure; Coupled; Cues; Data; Disinhibition; Distal; Dopamine; Dopamine D1 Receptor; Dopamine D2 Receptor; Dopamine Receptor; Dose; Drug usage; Dynorphins; Electrophysiology (science); Enkephalins; Epidemiology; Foundations; Genotype; Globus Pallidus; Goals; Health; Immunohistochemistry; Intake; Knock-out; Knockout Mice; Lead; Link; Long-Term Depression; Measures; Mediating; Messenger RNA; Mission; Motivation; Mus; National Institute of Drug Abuse; Neurons; Opioid; Opioid Antagonist; Opioid Peptide; Opioid Receptor; Opioid agonist; Opsin; Outcome; Output; Pathway interactions; Peptides; Pharmaceutical Preparations; Pharmacology; Population; Procedures; Protease Inhibitor; Protocols documentation; Psychological reinforcement; Public Health; Receptor Signaling; Recording of previous events; Regulation; Reporting; Research; Rewards; Saline; Signal Transduction; Slice; Source; Surveys; Synaptic plasticity; Testing; Training; Western Blotting; Work; cocaine cue; cocaine exposure; cocaine reward; cocaine seeking; cocaine self-administration; cocaine use; conditioned place preference; drug abstinence; endogenous opioids; gamma-Aminobutyric Acid; insight; motivated behavior; mu opioid receptors; neural circuit; neuronal excitability; novel; optogenetics; preference; response; restraint; stem; transmission process

PROJECT SUMMARY. Recent epidemiological reports indicate that cocaine use increased by 45% from 2013 to 2018. Cocaine-induced increase in striatal dopamine levels is linked to its rewarding effects. However, the striatal neural circuits driving cocaine abuse are not clearly defined. Thus, there is a critical need to delin- eate how the striatal circuits downstream of cocaine-induced dopamine release control cocaine seeking and taking. The overall objective of this proposal is to determine the mechanisms by which cocaine affects GABA transmission between the two principal neurons of the striatum, the D1-MSNs and D2-MSNs, to ultimately regulate drug seeking and taking. Our central hypothesis is that cocaine-enhances levels of the opioid peptide enkephalin, which acts via mu-opioid receptors (MOR) expressed in axon collaterals of D1- and D2-MSNs to facilitate cocaine seeking and taking. We will test this in two specific aims: Aim 1: Determine the mechanisms for how cocaine affects plasticity of intra-striatal GABA trans- mission. Based on our preliminary data, we hypothesize that a history of cocaine increases enkephalin re- lease from D2-MSNs, which induces MOR-dependent long-term depression of intra-striatal GABA transmis- sion onto D1-MSNs. We will test this by performing whole cell electrophysiology in MSN-selective MOR and enkephalin knockouts with a history of cocaine or saline exposure, and record GABA transmission between MSNs and MSN excitability. Pharmacology will be used to infer heightened enkephalin tone in electrophysi- ology recordings, and this will be confirmed by RNAscope, immunohistochemistry, Western blot and our MSN- selective enkephalin knockout. Aim 2: Determine how opioid regulation of intra-striatal circuits drive cocaine seeking and taking. Based on our preliminary data we hypothesize that enkephalin released from D2-MSNs acts on MORs in axon collaterals of D1- and D2-MSNs to suppress intra-striatal GABA and facilitate cocaine reward. We will test this using operant cocaine self-administration procedures in MSN-selective MOR and enkephalin knock- out mice. We will determine how intra-striatal GABA transmission from MSNs contributes to cocaine seeking by selectively inhibiting D1-MSN or D2-MSN striatal axon collaterals using a novel Gi-coupled opsin during a cued cocaine seeking task. Successful completion of the proposed research will elucidate how endogenous opioids regulate intra- striatal GABA transmission, and how cocaine impinges upon this mechanism to affect circuit activity. Moreo- ver, this research will provide novel insights on the mechanisms of cocaine abuse by establishing a link be- tween opioid-mediated regulation of intra-striatal GABA transmission and cocaine seeking and taking. This research will also lay the groundwork for our long-term goal of determining the circuit mechanisms driving synergistic reward when opiates and cocaine are co-abused.

项目摘要。最近的流行病学报告表明，可卡因的使用率从 2013年至2018年。可卡因诱导的纹状体多巴胺水平的升高与其奖励作用有关。然而， 尚未明确定义驾驶可卡因滥用的纹状体神经回路。因此，迫切需要描述 吃可卡因诱导的多巴胺释放控制可卡因和寻求可卡因的纹状体电路如何 服用。该提案的总体目的是确定可卡因影响GABA的机制 纹状体的两个主要神经元，D1-MSN和D2-MSN之间的传播，最终 调节毒品寻求和服用。我们的中心假设是阿片类肽的可卡因增强水平 Enkephalin，通过在D1-和D2-MSN的轴突侧支中表达的MU-阿片受体（MOR）起作用 促进可卡因寻求和服用。我们将以两个具体目标进行测试： AIM 1：确定可卡因如何影响纹状体GABA转移的可塑性的机制 使命。基于我们的初步数据，我们假设可卡因的史增加了脑链蛋白 D2-MSN的租赁，该租赁诱导了MOR依赖性的长期乳化性GABA TRANSMIS- 在D1-MSNS上。我们将通过在MSN选择性MOR中进行全细胞电生理和 Enkephalin淘汰赛具有可卡因或盐水暴露史，并记录GABA的传播 MSN和MSN兴奋性。药理学将用于推断电渗透中的增强的Enkephalin张力 rnascope，免疫组织化学，Western印迹和我们的MSN-将证实这一点 选择性Enkephalin淘汰赛。 AIM 2：确定阿片类及时电路的调节是如何驱动可卡因寻求和服用的。 基于我们的初步数据，我们假设从D2-MSN释放的Enkephalin在MORS上作用于 D1-和D2-MSN的轴突侧支，以抑制纹状体内GABA并促进可卡因奖励。我们将 使用MSN选择性MOR和Enkephalin敲门中的可卡因自我管理程序进行测试 出去老鼠。我们将确定MSN中纹状体内GABA的传播如何有助于可卡因寻求可卡因 通过选择性抑制D1-MSN或D2-MSN纹状体轴突侧支，使用新型的GI耦合Opsin在A期间 提示可卡因寻求任务。 拟议研究的成功完成将阐明内源性阿片类药物如何调节内部 纹状体GABA的传播，以及可卡因如何影响这种机制影响电路活性。多 VER，这项研究将通过建立联系来提供有关可卡因滥用机制的新见解。 补间阿片类药物介导的纹状体内GABA传播和可卡因寻求和服用的调节。这 研究还将为确定驱动电路机制的长期目标奠定基础 当鸦片和可卡因共同虐待时，协同奖励。