Relapse-suppressing neuronal ensembles in cocaine addiction

描述（由申请人提供）：可卡因成瘾是一种以强迫性可卡因使用为特征的慢性复发性疾病。在过去的几十年里，NIDA一直非常积极地支持临床和临床前研究，旨在了解能够促进可卡因寻求和渴望的因素的动机和神经生物学影响。不幸的是，大多数旨在阻止这些促进复发因素的干预措施（例如，抗渴望药物）在临床试验中被证明是无效的。因此，我们认为，至关重要的是要做出战略转变，调查能够抑制（而不是促进）可卡因寻求、渴望和最终复发的因素。在此前提下，我们开发了一个“遗漏线索诱导抑制（OCIS）范式”，以便系统地评估具有强迫性可卡因使用史的大鼠的可卡因遗漏（不可用）信号的复发抑制潜力。初步结果首次证明，遗漏线索能够抑制成瘾——比如可卡因的寻求。OCIS和可卡因寻求的消失在行为水平上存在显著差异（与OCIS不同，消失在抑制可卡因可用性线索和可卡因本身促进复发的能力方面是无效的），这一事实使它们在神经生物学水平上也存在差异的可能性成为可能。使用OCIS范式作为实验的基础，该项目将测试一个总体假设，即成瘾-如可卡因寻求习惯的OCIS涉及奖励回路中不同的神经元集合。在Specific Aim 1中，Fos/NeuN双标记染色（一种绘制“激活”神经元集合图的免疫组织化学工具）将用于定位被遗漏线索激活的神经元集合。在Specific Aim 2中，将使用Daun02失活方法（一种选择性破坏Fos阳性“激活”神经元的新型药物遗传学技术）来确定内侧前额叶皮层内介导OCIS的神经元群。根据R21应用的范围，拟议的实验是探索性和发展性的，但可能由于几个原因而获得高回报。首先，目前还没有研究系统地考察了在有强迫性可卡因使用史的大鼠中抑制可卡因寻求的大脑机制。其次，Daun02失活方法尚未应用于确定介导任何形式的药物寻求抑制的神经元集合。重要的是，这是目前唯一可用于检查特定神经元集合的行为贡献的方法。第三，对OCIS的神经生物学一无所知。总之，该项目旨在为未来的系统研究提供基础，以揭示遗漏线索强大的复发抑制潜力背后的大脑机制。这种调查可能导致更有效的干预措施，以治疗可卡因成瘾的长期复发性质。

DESCRIPTION (provided by applicant): Cocaine addiction is a chronic relapsing disorder characterized by compulsive cocaine use. Over the past few decades, NIDA has very actively supported clinical and preclinical research designed to understand the motivational and neurobiological impacts of factors capable of promoting cocaine seeking and craving. Unfortunately, most of the interventions (e.g., anti-craving medications) aimed to block these relapse- promoting factors have been proven to be ineffective in clinical trials. Therefore, we believe that it is critical to make a strategic shift to investigate the factors capable of suppresing (as opposed to promoting) cocaine seeking, craving and ultimately relapse. On this premise, we developed an "omission cue-induced suppression (OCIS) paradigm" in order to systematically evaluate the relapse-suppressing potential of cues signaling cocaine omission (unavailability) in rats with a cocaine history associated with compulsive cocaine use. The preliminary results demonstrate for the first time that omission cues are capable of suppressing addiction-like cocaine seeking. The fact that OCIS and extinction of cocaine seeking significantly differ at behavioral level (unlike OCIS, extinction is ineffective at suppressing the relapse-promoting capacity of cocaine availability cues and cocaine itself) leaves open the possibility that they als differ at neurobiological level. Using the OCIS paradigm as the base for the proposed experiments, this project will test the overarching hypothesis that the OCIS of addiction-like cocaine-seeking habit involves distinct neuronal ensembles within the reward circuit. In Specific Aim 1, Fos/NeuN double-label staining (an immunohistochemical tool to map "activated" neuronal ensembles) will be used to localize neuronal ensembles activated by omission cues. In Specific Aim 2, the Daun02 inactivation method (a novel pharmacogenetic technique to selectively disrupt Fos positive "activated" neurons) will be used to determine the neuronal ensembles within the medial prefrontal cortex mediating OCIS. In line with the scope of R21 applications, the proposed experiments are exploratory and developmental but possibly with high reward for several reasons. First, no study has yet systematically examined the brain mechanisms that suppress cocaine seeking in rats with a drug history associated with compulsive cocaine use. Second, the Daun02 inactivation method has not been applied to determine neuronal ensembles mediating any form of drug-seeking suppression. Importantly, this is the only method currently available to examine the behavioral contribution of specific neuronal ensembles. Third, nothing is known of the neurobiology of OCIS. In summary, the proposed project is designed to provide the groundwork for future systemic research to uncover the brain mechanisms underlying the robust relapse-suppressing potential of omission cues. Such investigation may lead to more effective interventions to treat the chronically relapsing nature of cocaine addiction.