Plasticity in nucleus accumbens spines during incubation of cocaine craving

可卡因渴望孵化期间伏隔核棘的可塑性

基本信息

批准号：
9060918
负责人：
Daniel Tommis Christian
金额：
$ 5.61万
依托单位：
ROSALIND FRANKLIN UNIV OF MEDICINE & SCI
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-20 至 2017-04-19
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9060918
关键词：
AMPA Receptors Abstinence Animals Appearance Behavior Brain region Cocaine Cocaine Dependence Cocaine Users Computer software Confocal Microscopy Cues Dendritic Spines Development Drug Addiction Drug abuse Drug usage Electrophysiology (science)Excitatory Synapse Exhibits Glutamate Receptor Goals Health Image Incubated Individual Measurement Mediating Mentors Mission Modeling Modification Molecular Morphology N-Methylaspartate Neurons Nucleus Accumbens Pattern Pharmaceutical Preparations Procedures Process Property Rattus Regimen Relapse Research Role Saline Self Administration Signal Transduction Synapses Synaptic Transmission Synaptic plasticity System Testing Therapeutic Agents Time Training United States National Institutes of Health Vertebral column Withdrawal Wolves Work base burden of illness cocaine exposure craving density drug addict drug craving drug of abuse drug relapse lucifer yellow neuroadaptation novel skills synaptic function therapeutic target treatment strategy two-photon

项目摘要

DESCRIPTION (provided by applicant): A major problem in treating cocaine addiction is the long lasting vulnerability to relapse, even after months of abstinence. This persistent vulnerability suggests that long lasting neuroadaptations contribute to relapse behavior. Understanding these persistent adaptations is critical to the development of therapeutic agents. Our lab uses a rat model of cocaine addiction, termed the incubation model, in which cue-induced cocaine craving progressively intensifies (incubates) over the first 2 months of withdrawal from extended access cocaine self-administration. We focus on the nucleus accumbens (NAc), a brain region critically involved in the reinforcing properties of drugs of abuse. We showed previously that Ca2+-permeable AMPARs (CP-AMPARs) accumulate in excitatory synapses onto medium spiny neurons of the NAc after 3-4 weeks of withdrawal and then persist for months. Once they accumulate in NAc synapses, these CP-AMPARs mediate the expression of incubated cue-induced cocaine craving. Therefore mechanisms regulating CP-AMPARs are potential therapeutic targets. While our previous work has gathered detailed information on AMPAR plasticity during incubation, little is known about how NMDARs or structural alterations to dendritic spines contribute. Prior studies examining these parameters have typically used non-contingent cocaine regimens which are not directly useful for assessing cocaine craving. The objective of this proposal is to characterize spine morphology and glutamate receptor-mediated Ca2+ signaling in NAc dendritic spines at a withdrawal time before CP-AMPARs accumulate (WD15) and a time after CP-AMPAR accumulation (WD35), to identify plasticity at the single spine level that is associated with CP-AMPAR accumulation. My central hypothesis is that incubation is accompanied by dendritic spine remodeling that involves the formation of spines that contain CP-AMPARs but not NMDARs. This hypothesis will be tested by pursuing two specific aims: 1) Characterize dendritic spine density and morphology in medium spiny neurons (MSNs) during incubation of cocaine craving. Single NAc neurons will be filled with Lucifer yellow, imaged with confocal microscopy, and analyzed with NeuronStudio software. 2) Determine if cocaine and control rats differ in NMDAR and AMPAR mediated Ca2+ influx at the individual spine level in NAc MSN. 2-photon Ca2+ imaging with concurrent electrophysiological measurements will be used to analyze the contribution of CP-AMPARs and NMDARs to Ca2+ signaling in NAc spines on WD15 or WD35 from saline or cocaine self-administration. Caged NMDA and AMPA compounds will be used to dissect functional contributions of NMDARs and CP-AMPARs at the single spine level. These studies will provide a novel window on cocaine-induced neuroadaptations at the single spine level and further our understanding of relationships between glutamate receptor and spine plasticity. While this work is underway, I will participate in a Training Plan that employs coursework, mentoring, and collaborative interactions to develop the non-bench skills needed to reach my goal of becoming a PI in an academic setting.

描述（由申请人提供）：治疗可卡因成瘾的一个主要问题是即使在戒断数月之后，仍容易复发。这种持续存在的脆弱性表明，长期持续的神经适应会导致旧病复发。了解这些持续的适应对于治疗药物的开发至关重要。我们的实验室使用可卡因成瘾的大鼠模型，称为“潜伏模型”，其中提示诱导的可卡因渴望在停止长期使用可卡因自我给药的前两个月内逐渐增强（潜伏）。我们重点关注伏隔核（NAc），这是一个与增强滥用药物特性密切相关的大脑区域。我们之前表明，停药 3-4 周后，Ca2+ 渗透性 AMPAR（CP-AMPAR）会在 NAc 中型多棘神经元的兴奋性突触中积累，然后持续数月。一旦它们在 NAc 突触中积累，这些 CP-AMPAR 就会介导孵化线索诱导的可卡因渴望的表达。因此，调节 CP-AMPAR 的机制是潜在的治疗靶点。虽然我们之前的工作收集了有关孵化过程中 AMPAR 可塑性的详细信息，但对于 NMDAR 或树突棘的结构改变如何发挥作用却知之甚少。先前检查这些参数的研究通常使用非偶然可卡因方案，该方案不能直接用于评估可卡因渴望。该提案的目的是在 CP-AMPAR 积累之前 (WD15) 和 CP-AMPAR 积累之后 (WD35) 的退出时间 (WD35) 表征 NAc 树突棘中的脊柱形态和谷氨酸受体介导的 Ca2+ 信号传导，以确定树突棘的可塑性。与 CP-AMPAR 积累相关的单脊柱水平。我的中心假设是，孵化伴随着树突棘重塑，涉及包含 CP-AMPAR 但不包含 NMDAR 的树突棘的形成。该假设将通过追求两个具体目标来检验：1）表征可卡因渴望孵化期间中型多棘神经元（MSN）的树突棘密度和形态。单个 NAc 神经元将被荧光黄填充，用共焦显微镜成像，并用 NeuronStudio 软件进行分析。 2) 确定可卡因和对照大鼠在 NAc MSN 中个体脊柱水平的 NMDAR 和 AMPAR 介导的 Ca2+ 流入方面是否存在差异。 2 光子 Ca2+ 成像与并发电生理测量将用于分析 CP-AMPAR 和 NMDAR 对来自盐水或可卡因自我给药的 WD15 或 WD35 上的 NAc 棘中 Ca2+ 信号传导的贡献。笼中的 NMDA 和 AMPA 化合物将用于剖析 NMDAR 和 CP-AMPAR 在单脊柱水平上的功能贡献。这些研究将为可卡因诱导的单脊柱水平的神经适应提供一个新的窗口，并进一步加深我们对谷氨酸受体与脊柱可塑性之间关系的理解。在这项工作进行期间，我将参加一项培训计划，该计划采用课程作业、指导和协作互动来培养实现我在学术环境中成为 PI 的目标所需的非工作技能。