Investigating the ventral pallidum-ventral tegmental area circuit in cocaine relapse

项目概要/摘要： 在过去十年中，可卡因滥用和可卡因过量死亡的增加说明了缺乏治疗药物。 对可卡因使用障碍（CUD）患者进行干预。戒毒是可卡因唯一的治疗方法 但大多数患有CUD的人都容易复发。新型CUD的研制 治疗依赖于对驱动可卡因渴望的神经机制的透彻理解， 复发在不同的神经元亚群中，突触引起分子适应，导致回路- 神经活动的特定变化。奖赏回路的一个关键节点是腹侧苍白球（VP），因为它接收到 来自几个区域的投入和项目，这些区域介导了寻求可卡因的行为。来自VP传入的活动 可卡因复吸需要腹侧被盖区（VTA投射VP神经元）;然而， 以及发生在VTA投射VP神经元内的分子适应，以促进可卡因寻找， 未知为了更好地了解CUD的病理学，本提案将研究 VTA投射VP神经元内的神经元活性和基因表达发生在线索诱导的VTA投射VP神经元内。 恢复可卡因寻求。使用可卡因静脉自我管理（IVSA）和化学遗传学 在小鼠中，我的初步数据重复了先前在大鼠中的发现，即腹侧被盖投射VP神经元是 恢复可卡因寻求。在这个提案中，我将采用IVSA，尖端的体内生物传感器， 化学遗传学和分子技术来研究VP神经元活性的回路特异性变化， 在可卡因成瘾的恢复过程中出现的基因表达。我假设可卡因与腹侧被盖区- 投射VP神经元，导致可卡因线索诱导的1）VTA投射VP神经元活性增强 和2）伴随药物寻求和复发的突触基因表达增加。在具体目标1中，我将 使用纤维光度法评估可卡因相关线索如何影响VTA内的模式钙活性， 在线索诱导的恢复过程中投射VP神经元。我还将研究如何化学发生抑制 VTA投射VP神经元影响VTA投射VP钙活性的变化， 可卡因相关线索在具体目标2，我将进行核糖体免疫沉淀与RNA测序 为了确定在VTA投射VP神经元内突触基因表达的增加是否发生在 恢复可卡因寻求。此外，我将研究是否抑制VTA投射VP神经元的活动， 使用化学遗传学和RNAScope防止基因表达的恢复诱导的变化。在一起， 这些实验将确定腹侧被盖投射VP神经元内的新机制， 恢复可卡因寻求。这个建议也将为我在新的研究领域提供强有力的培训 支持我在科学领域的独立职业道路

Project Summary/Abstract: Rises in cocaine misuse and cocaine overdose deaths over the last decade illustrate the lack of therapeutic interventions for individuals with cocaine use disorder (CUD). With abstinence as the only treatment for cocaine cravings, a majority of individuals with CUD are vulnerable to relapse. The development of novel CUD therapeutics relies on a thorough understanding of the neural mechanisms that drive cocaine craving and relapse. Cocaine causes molecular adaptations within distinct neuronal subpopulations that leads to circuit- specific changes in neural activity. A critical node of the reward circuit is the ventral pallidum (VP), as it receives input from and projects to several regions that mediate cocaine-seeking behaviors. Activity from VP afferents to the ventral tegmental area (VTA-projecting VP neurons) is required for cocaine relapse; however, the cellular and molecular adaptations that occur within VTA-projecting VP neurons to promote cocaine-seeking, are unknown. To better understand the pathology of CUD, this proposal will investigate how changes in neuronal activity and gene expression within VTA-projecting VP neurons occur within cue-induced reinstatement to cocaine-seeking. Using cocaine intravenous self-administration (IVSA) and chemogenetics in mice, my preliminary data replicates a previous finding in rats that VTA-projecting VP neurons are required for reinstatement of cocaine-seeking. In this proposal, I will employ IVSA, cutting-edge in vivo biosensors, chemogenetics and molecular techniques to investigate the circuit-specific changes in VP neuronal activity and gene expression that occur during reinstatement to cocaine-seeking. I hypothesize that cocaine engages VTA- projecting VP neurons, leading to cocaine cue-induced 1) enhancement of VTA-projecting VP neuronal activity and 2) increases in synaptic gene expression that accompany drug-seeking and relapse. In Specific Aim 1, I will use fiber photometry to assess how cocaine-associated cues affected patterned calcium activity within VTA- projecting VP neurons during cue-induced reinstatement. I will also examine how chemogenetic inhibition of VTA-projecting VP neurons impacts changes in VTA-projecting VP calcium activity following the presentation of cocaine-associated cues. In Specific Aim 2, I will perform ribosomal immunoprecipitation with RNA-Sequencing to determine whether increases in synaptic gene expression within VTA-projecting VP neurons occurs following reinstatement to cocaine-seeking. Further, I will examine whether inhibiting VTA-projecting VP neuronal activity prevents reinstatement-induced changes in gene expression using chemogenetics and RNAScope. Together, these experiments will identify novel mechanisms within VTA-projecting VP neurons neurons that mediate reinstatement to cocaine-seeking. This proposal will also provide me with strong training in new research areas that will support my independent career path in science.