GLUTAMATE RECEPTORS AND OPIOID DEPENDENCE: MOLECULES, CIRCUITS AND BEHAVIOR

描述（由申请人提供）：阿片类药物依赖的特征是在药物暴露终止后出现的负面生理和心理症状。由于这些症状可以通过持续使用药物来缓解或避免，因此依赖性有助于成瘾的循环。虽然依赖的神经基质知之甚少，但有证据表明，中央杏仁核（CeA）中的功能性离子型（NMDA和AMPA）谷氨酸受体在这种形式的阿片依赖性可塑性中起着关键作用。在PI当前研究科学家发展奖期间进行的研究表明，Cre-loxP技术可用于删除CeA神经元中的NMDA-NR 1（NR 1）受体亚基基因，并防止吗啡戒断诱导的厌恶，而不会影响身体症状。本提案的目标是通过测试以下全球性假设来扩展这些发现：中央杏仁核NMDA受体在与阿片类药物依赖相关的条件性厌恶和AMPA受体可塑性中发挥关键作用。这一假设将通过以下具体目标来解决：目标1将检验NR 1的CeA敲除将产生阿片类戒断厌恶的特异性抑制的假设。目的2将检验μ阿片受体（OR）和离子型谷氨酸受体在CeA神经元中共定位于树突和树突棘（即突触后）的假设。目的3将测试的假设，急性阿片类药物暴露可以影响的AMPA-GluR 2受体亚单位在CeA神经元的突触后位点，一个过程，可以抑制本地NR 1基因缺失的贩运。为了解决这些假设，国家的最先进的技术，包括时空敲除方法和定量超微结构分析的受体贩运，将采用阿片类药物依赖模型的背景下。这些研究应阐明参与吗啡使用相关的行为和神经可塑性的关键分子和细胞内过程的作用，从而扩大我们对阿片类药物依赖的神经遗传学和神经解剖学底物的认识。尽管类阿片具有临床疗效，但其滥用和成瘾倾向是公共卫生问题的一个重要来源。长期使用阿片类药物似乎会在边缘脑区域产生一个复杂的信号分子网络，特别是谷氨酸受体，产生类似于正常学习和记忆的神经变化。利用最先进的分子药理学和神经解剖学技术，该提案将确定谷氨酸受体在特定脑通路中阿片类药物依赖中的作用。通过阐明介导依赖不良后果的神经生物学过程，我们可以提供开发减少这些有害行为的药理学干预所需的关键信息。

DESCRIPTION (provided by applicant): Opioid dependence is characterized by negative physiological and psychological symptoms that arise following termination of drug exposure. Since these symptoms can be relieved or avoided by continued drug use, dependence contributes to the cycle of addiction. While the neural substrates of dependence are poorly understood, evidence is emerging that functional ionotropic (NMDA and AMPA) glutamate receptors in the central amygdala (CeA) play a critical role in this form of opioid-dependent plasticity. Studies conducted during the PI's current Research Scientist Development Award have shown that Cre-loxP technology can be used to delete the NMDA-NR1 (NR1) receptor subunit gene in CeA neurons and prevent morphine withdrawal-induced aversion, without affecting physical symptoms. The goal of the present proposal is to expand on these findings by testing the following global hypothesis: Central amygdala NMDA receptors play critical roles in both conditioned aversion and AMPA receptor plasticity associated with opioid dependence. This hypothesis will be addressed by the following Specific Aims: Aim 1 will test the hypothesis that CeA knockout of NR1 will produce a specific inhibition of opioid withdrawal aversion. Aim 2 will examine the hypothesis that mu-opioid receptors (OR) and ionotropic glutamate receptors are co-localized in dendrites and dendritic spines (i.e. postsynaptically) in CeA neurons. Aim 3 will test the hypothesis that acute opioid exposure can affect the trafficking of the AMPA-GluR2 receptor subunit at postsynaptic sites in CeA neurons, a process that can be inhibited by local NR1 gene deletion. To address these hypotheses, state-of-the-art technology, including spatial-temporal knockout methods and quantitative ultrastructural analysis of receptor trafficking, will be employed within the context of models of opioid dependence. These studies should elucidate the role of key molecules and intracellular processes involved in both behavioral and neural plasticity associated with morphine use, thus expanding our knowledge of the neurogenetic and neuroanatomical substrates of opioid dependence. Despite the clinical efficacy of opioids, their abuse and addictive liability are a significant source of public health problems. Chronic use of opioids appear to engage a complex network of signaling molecules, particularly glutamate receptors, in limbic brain regions that produce neural changes similar to those involved in normal learning and memory. Using state of the art molecular pharmacological and neuroanatomical techniques, this proposal will identify the role of glutamate receptors in opioid dependence in specific brain pathways. 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.