Characteristics and Function of Prefrontal Astrocyte Activity in Heroin-Seeking Behavior

项目概要/摘要 随着目前阿片类药物的流行处于国家危机水平，了解神经机制， 使用海洛因和重新寻求毒品是发现新的治疗策略的关键。暴露于刺激 先前与海洛因的欣快效应配对的药物被认为维持了海洛因的习惯性使用和寻求 行为。因此，这些海洛因条件作用将药物使用的负面后果延长到很久以前。 停止背内侧前额叶皮层（dmPFC）的失调是海洛因习惯性使用的驱动因素 以及线索诱导的复发，然而离散神经网络组件如何编排海洛因寻求行为 仍然不太清楚。使用一种新的头部固定的自我给药（SA）小鼠行为模式， 同步双光子钙成像，最近的数据从我们的实验室表明，独特的兴奋性神经元 集合出现并编码与海洛因条件线索和海洛因寻求行为相关的信息。 星形胶质细胞是神经元回路中的关键调节元件，并且胶质细胞钙事件对于调节星形胶质细胞的功能是必要的。 神经网络活动然而，dmPFC星形胶质细胞如何促进海洛因相关的神经元编码， 线索和寻求海洛因的行为仍然未知。本项目的目标是调查 dmPFC星形胶质细胞（1）参与整个海洛因使用过程，（2）因果影响周围神经元 总体动力学和复发行为。为此，我们将综合运用各种当代战略， 包括体内双光子成像和化学遗传学工具，以测量和操纵dmPFC细胞活性 在海洛因使用和复吸期间。 目前的提案将是第一个测量习惯性海洛因使用过程中星形胶质细胞钙动力学的提案， 复发，并确定星形胶质细胞活性对神经元编码和海洛因寻求的因果影响 行为我建议使用多病毒方法和体内双光子显微镜来可视化和跟踪 在头固定的小鼠中，在海洛因-SA、消退和恢复过程中个体星形胶质细胞钙事件（Aim 1）。随后，我将采用双光子成像结合头部固定海洛因-SA来测量和跟踪 单细胞分辨率的神经元活动。然后，我将刺激星形胶质细胞特异性hM 4D（Gi）设计受体， 并评估神经元整体活动和海洛因寻求行为的后果（目的 2）。根据我的初步数据和我的导师团队发表的工作，我假设dmPFC 星形胶质细胞在海洛因使用的开始和海洛因寻求的恢复期间显示出偏向性激活（目的1） 并且星形胶质细胞钙事件直接协调周围神经元网络动力学和复发 行为（目标2）。这些数据将提供dmPFC网络活动如何编排的整体视图 习惯性使用海洛因和寻求行为。目前的建议是第一个跟踪整个星形胶质细胞活动 药物使用和因果牵连神经胶质细胞在神经元编码的药物条件的线索和复发行为。

Project summary/Abstract With the current opioid epidemic at a national crisis level, understanding the neural mechanisms governing heroin use and relapse to drug seeking is key to discovering new treatment strategies. Exposure to stimuli previously paired with the euphoric effects of heroin are thought to maintain habitual heroin use and seeking behaviors. These heroin-conditioned effects therefore extend the negative consequences of drug use well past cessation. Dysregulation of the dorsal medial prefrontal cortex (dmPFC) is a driving factor in habitual heroin use and cue-induced relapse, yet how discrete neural network components orchestrate heroin-seeking behavior remains less clear. Using a novel head-fixed self-administration (SA) mouse behavioral paradigm and simultaneous two-photon calcium imaging, recent data from our laboratory indicates unique excitatory neuronal ensembles emerge and encode information related to heroin-conditioned cues and heroin-seeking behaviors. Astrocytes are key regulatory elements in neuronal circuits and glial calcium events are necessary for modulating neuronal network activity. However, how dmPFC astrocytes contribute to neuronal encoding of heroin-related cues and heroin-seeking behaviors remains unknown. The goal of the current project is to investigate that dmPFC astrocytes (1) are engaged throughout heroin use and (2) causally influence surrounding neuronal ensemble dynamics and relapse behaviors. To this end, we will use a combination of contemporary strategies, including in vivo two-photon imaging and chemogenetic tools, to measure and manipulate dmPFC cellular activity during heroin use and relapse. The current proposal will be the first to measure astrocytic calcium dynamics throughout habitual heroin use and relapse and determine the causal influence of astrocytic activity on neuronal encoding and heroin-seeking behavior. I propose to use a multi-virus approach and in vivo two-photon microscopy to visualize and track individual astrocytic calcium events throughout heroin-SA, extinction, and reinstatement in head-fixed mice (Aim 1). Subsequently, I will employ two-photon imaging coupled with head-fixed heroin-SA to measure and track neuronal activity with single-cell resolution. I will then stimulate an astrocyte-specific hM4D(Gi) designer receptor during relapse and assess the consequence for neuronal ensemble activity and heroin-seeking behavior (Aim 2). Based on my preliminary data and published work of my mentorship team, I hypothesize that dmPFC astrocytes display biased activation during the onset of heroin use and reinstatement of heroin seeking (Aim 1) and that astrocytic calcium events directly coordinates surrounding neuronal network dynamics and relapse behavior (Aim 2). These data would provide a wholistic view of how dmPFC network activity orchestrates habitual heroin use and seeking behavior. The current proposal is the first to track astrocytic activity throughout drug use and causally implicate glia in the neuronal encoding of drug-conditioned cues and relapse behavior.