Muscarinic Modulation of the Basolateral Amygdala

 描述（由申请人提供）：通过杏仁核基底外侧（BL）核中的毒蕈碱乙酰胆碱受体（mAChR）的信号传导在情绪记忆的形成和消退中起着重要作用。因此，在包括人类在内的所有哺乳动物中，BL比基底前脑的任何其他靶点接受更强的胆碱能神经支配。行为学研究表明，BL中mAChRs的激活增强了恐惧记忆，而这些受体的阻断阻止了记忆的巩固。此外，阿尔茨海默氏病以及神经精神障碍如精神分裂症，通常与情绪障碍有关，被认为至少部分是由异常胆碱能传递引起的。事实上，在阿尔茨海默氏症患者中，BL的胆碱能输入的退化程度与他们的情感事件记忆受损相关。这些研究结果清楚地表明，治疗调制的mAChR介导的机制在BL可能是重要的治疗一些主要的神经精神疾病，涉及情感学习障碍。尽管mAChRs在情绪记忆的生理学和病理生理学中的重要性，但还没有研究系统地研究mAChRs调节BL功能的分子、细胞和网络水平机制。本提案中概述的研究将联合收割机多重标记电子显微镜和多重标记共聚焦免疫荧光与最先进的电生理学和光遗传学相结合，以解决这一重大知识缺口。我们的长期目标是要了解如何毒蕈碱受体调节杏仁核可以操纵治疗的目的。这里的目的是确定如何突触释放乙酰胆碱，作用于mAChRs，调节BL中的神经元活动。我们的中心假设是，不同的mAChRs在不同的神经元亚群发挥离散的作用，在调节神经元振荡，过滤显着的信号和加强在BL的mAChRs的输入。我们的假设是基于初步的数据显示，mAChRs强烈调制BL电路的方式不同，在其他大脑区域的报告。这一假设将通过追求三个具体目标进行检验：1）定义神经元兴奋性和振荡活动的毒蕈碱调制 2）确定突触前mAChRs对突触传递和可塑性的频率依赖性门控; 3）确定mAChRs对BL中突触传递和可塑性的功能作用。该项目包括BRAIN计划的几个优先事项/主题，包括“表征神经系统中的细胞类型”，开发工具以“操纵这些精确定义的神经元”，创建“大脑结构图”以及“跨学科合作的边界”。关于BL电路的mAChR调节的信息对于开发改善严重神经精神障碍、治疗药物成瘾和减少阿尔茨海默病产生的情感缺陷的疗法将是至关重要的。

 DESCRIPTION (provided by applicant): Signaling through muscarinic acetylcholine receptors (mAChRs) in the basolateral (BL) nucleus of the amygdala plays an essential role in the formation and extinction of emotional memory. Accordingly, in all mammals, including humans, the BL receives more robust cholinergic innervation than any other target of the basal forebrain. Behavioral studies have demonstrated that activation of mAChRs in BL enhances fear memories, whereas blockade of these receptors prevents memory consolidation. Moreover, Alzheimer's disease as well as neuropsychiatric disorders such as schizophrenia, which are commonly associated with emotional disturbances, are thought to result, at least in part, from abnormal cholinergic transmission. Indeed, in Alzheimer's patients the extent of degeneration of cholinergic input to BL is correlated with their impairment of emotional event memory. These findings clearly suggest that therapeutic modulation of mAChR-mediated mechanisms in the BL could be important for treating a number of major neuropsychiatric diseases involving impairments in emotional learning. Despite the importance of mAChRs in the physiology and pathophysiology of emotional memory, there have been no studies that have systematically examined the molecular, cellular, and network-level mechanisms by which mAChRs regulate BL function. The studies outlined in this proposal will combine multiple-labeling electron microscopy and multiple-labeling confocal immunofluorescence with state-of-the-art electrophysiology and optogenetics to address this significant knowledge gap. Our long term goal is to understand how muscarinic receptor regulation of the amygdala can be manipulated for therapeutic purposes. The objective here is to determine how synaptically released acetylcholine, acting on mAChRs, regulates neuronal activity in the BL. Our central hypothesis is that distinct mAChRs on different neuronal subpopulations play discrete roles in regulating neuronal oscillations, filtering salient signals and strengthening glutamatergic inputs in the BL. Our hypothesis is based on preliminary data which reveal that mAChRs strongly modulate BL circuits in a manner distinct from that reported in other brain regions. This hypothesis will be tested by pursuing three specific aims: 1) To define muscarinic modulation of neuronal excitability and oscillatory activity at pyramidal cells and interneurons in the BL; 2) To define frequency-dependent gating of glutamatergic and GABAergic transmission by presynaptic mAChRs; and 3) To determine the functional effect of mAChRs on synaptic transmission and plasticity in the BL. This project encompasses several of the priorities/themes of the BRAIN Initiative, including "characterizing cell types in the nervous system", developing tools to "manipulate these precisely defined neurons", creating "structural maps of the brain", and "crossing boundaries in interdisciplinary collaborations. Information about mAChR regulation of BL circuits will be critical for the development of therapies to ameliorate severe neuropsychiatric disorders, treat drug addiction and diminish the emotional deficits produced by Alzheimer's disease.