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.

项目总结。最近的流行病学报告表明，可卡因的使用量从 2013至2018年。可卡因引起的纹状体多巴胺水平的增加与可卡因的奖赏效应有关。然而， 驱动可卡因滥用的纹状体神经回路没有明确的定义。因此，迫切需要-- 可卡因诱导的多巴胺释放的纹状体环路如何控制可卡因的寻找和 夺取。这项提案的总体目标是确定可卡因影响GABA的机制。 纹状体的两个主要神经元--D_1-MSN和D_2-MSN之间的传递最终 规范寻毒吸毒行为。我们的中心假设是可卡因提高了阿片肽的水平 脑啡肽，它通过在D_1和D_2-MSN轴突侧支表达的u-阿片受体(MOR)作用于 为寻找和服用可卡因提供便利。我们将在两个具体目标中测试这一点： 目的1：确定可卡因影响纹状体内GABA可塑性的机制。 任务。根据我们的初步数据，我们假设可卡因的历史增加脑啡肽再- 从D2-MSNS中租来的，它诱导纹状体内GABA传递的吗啡依赖的长期抑制。 Sion上的d1-MSNS。我们将通过对MSN选择性MOR进行全细胞电生理来测试这一点 有可卡因或盐水暴露史的脑啡肽敲除，并记录GABA在 MSNS和MSN兴奋性。药理学将被用来推断电物理中脑啡肽水平的升高- 生物学记录，这将通过RNAScope，免疫组织化学，Western印迹和我们的MSN- 选择性脑啡肽基因敲除。 目的2：确定纹状体内回路的阿片类药物调节如何驱动可卡因的寻找和服用。 根据我们的初步数据，我们假设从D2-MSNS释放的脑啡肽作用于MORS。 D_1和D_2-MSN的轴突侧支抑制纹状体内GABA和促进可卡因奖赏。我们会 在MSN选择性MOR和脑啡肽敲击中使用可卡因自我给药程序来测试这一点 把老鼠赶出去。我们将确定来自MSN的纹状体内GABA传递如何有助于可卡因寻求 通过使用一种新型的Gi偶联视蛋白选择性地抑制D1MSN或D2MSN纹状体轴突侧支 提示可卡因寻找任务。 这项拟议研究的成功完成将阐明内源性阿片类药物如何调节细胞内 纹状体GABA传递，以及可卡因如何影响这一机制以影响电路活动。莫雷奥- 此外，本研究将通过建立与可卡因滥用之间的联系，为研究可卡因滥用的机制提供新的见解。 阿片类药物对纹状体内GABA传递的调节与可卡因的寻找和服用。这 研究还将为我们确定驱动电路机制的长期目标奠定基础 当鸦片类药物和可卡因共同滥用时的协同奖励。