AMYGDALA AMPA GLUR2 DELETION AND OPIOID DEPENDENCE

描述（由申请人提供）：阿片类药物依赖是慢性阿片类药物使用的主要并发症，有助于成瘾综合征。除了避免戒断症状外，戒断相关线索的体验也可能在药物服用行为中起重要作用。因此，阐明介导慢性阿片类药物使用不良后果的神经生物学过程，特别是涉及厌恶学习的作用，可能为管理成瘾性疾病提供重要信息。有证据表明，杏仁核中央核的ampa型谷氨酸受体可能是阿片依赖的重要分子底物。AMPA-GluR2 （GluR2）受体亚基是AMPA受体的主要组成部分，决定钙的通透性，与药物依赖有关，并在CeA中表达。表达AMPA受体的GluR2的活性受nmda型谷氨酸受体的调节，而nmda型谷氨酸受体本身是神经和行为适应性的分子底物。尽管有这些发现，没有直接证据表明GluR2基因在CeA中的表达是阿片类药物依赖表达的必要条件。本应用程序的主要目的是开发AMPA-GluR2受体亚基的时空缺失，以验证中央杏仁核神经元突触后表达GluR2对阿片戒断诱导的条件性场所厌恶（CPA）是必要的假设。这一假设将通过局部微量注射表达Cre重组酶的嗜神经腺相关病毒载体，在GluR2粘接小鼠的中央杏仁核神经元中产生GluR2突触后缺失来研究。局部基因缺失的生存能力将通过光和电子免疫组织化学和原位杂交检测。CeA GluR2缺失的表型效应将通过行为测量来确定，包括退缩诱导的条件厌恶。该项目有望增强我们对神经元谷氨酸受体基因表达在阿片类药物依赖中的作用的理解，特别是基于AMPA-GluR2的小分子或基因治疗的可能价值。尽管阿片类药物具有临床疗效，但它们的滥用和成瘾性是公共卫生问题的重要来源。阿片类药物可能通过激活杏仁核谷氨酸受体产生持久的影响，杏仁核谷氨酸受体是在神经可塑性以及学习和记忆中起重要作用的分子。利用最先进的分子神经药理学技术，本提案将确定ampa型谷氨酸受体GluR2亚基在杏仁核中与阿片类药物依赖有关的作用。通过阐明介导依赖不良后果的神经生物学过程，我们可以为开发减少这些有害行为的药理学干预提供关键信息。

DESCRIPTION (provided by applicant): Opioid dependence is a major complication of chronic opioid use that contributes to the syndrome of addiction. In addition to the avoidance of withdrawal symptoms, experience of withdrawal-associated cues may also play an important role in drug taking behavior. Thus, elucidating the neurobiological processes that mediate the adverse consequences of chronic opioid use, particularly involving the role of aversive learning, may provide critical information for managing addictive disease. There is evidence that ionotropic AMPA-type glutamate receptors in the central nucleus of the amygdala (CeA) may be important molecular substrates of opioid dependence. The AMPA-GluR2 (GluR2) receptor subunit is a major component of AMPA receptors, determines calcium permeability, has been implicated in drug dependence, and is expressed in the CeA. The activity of GluR2 expressing AMPA receptors is modulated by NMDA-type glutamate receptors, which are themselves, established molecular substrates of neural and behavioral adaptability. Despite these findings, there is no direct evidence that GluR2 gene expression in the CeA is necessary for the expression of opioid dependence. The primary goal of this application is to develop a spatial-temporal deletion of the AMPA-GluR2 receptor subunit to test the hypothesis that postsynaptic expression of GluR2 in central amygdala neurons is necessary for opioid withdrawal- induced conditioned place aversion (CPA). This hypothesis will be investigated by producing a postsynaptic deletion of GluR2 in central amygdala neurons of floxed GluR2 mice via local microinjection of a neurotropic adenoassociated viral vector expressing Cre recombinase. The viability of local gene deletion will be tested by light and electron immunohistochemistry and in situ hybridization. The phenotypic effects of CeA GluR2 deletion will be determined by behavioral measurements, including withdrawal-induced conditioned place aversion. This project is expected to enhance our understanding of the role of neuronal glutamate receptor gene expression in opioid dependence, particularly with respect to the possible value of AMPA-GluR2 based small molecule or gene therapeutics. Despite the clinical efficacy of opioids, their abuse and addictive liabilities are significant sources of public health problems. Opioids may produce their long-lasting effects by activating amygdala glutamate receptors, molecules that play important roles in neural plasticity, as well as learning and memory. Using state of the art molecular neuropharmacological techniques, this proposal will identify the role of the AMPA-type glutamate receptor GluR2 subunit in the amygdala with respect to opioid dependence. By elucidating the neurobiological processes that mediate the adverse consequences of dependence, we may provide critical information needed to develop pharmacological interventions for reducing these deleterious actions.