Physiology and function of amygdalo-cortical endocannabinoid signaling

项目总结 压力暴露是发展负面情绪状态的普遍风险因素 神经精神障碍，如焦虑、抑郁和创伤后应激障碍(PTSD)。然而， 应激诱导的神经病理和由此产生的病理行为状态之间的因果联系仍然存在 难以捉摸。有重要的证据表明，压力会导致各种各样的形态和 关键结节--内侧前额叶皮质(PlPFC)初级成分的神经化学适应 与情绪行为的自上而下调节密切相关的结构。事实上，易患上 创伤应激暴露的抑郁效应与该区域内突触的增强有关。 有趣的是，大麻类化合物的抗焦虑作用主要是通过激活CB1来实现的。 MPFC内谷氨酸能轴突终末的受体。应激本身会动态改变内源性大麻素 (ECB)mPFC内的信号转导，因为应激暴露导致EC配体2- AG在mPFC中，据称代表了一种自适应应对反应，缓冲了 应激暴露引起的负面生理效应。然而，目前还完全不清楚是什么神经 ECB调节通路以诱导这种对应激诱导的行为病理的缓冲效应。在我们的 研究中，我们正在观察杏仁基底外侧核(BLA)这一大脑区域对plPFC的投射。 这与情感障碍和创伤后应激障碍的病理生理学密切相关。BLA发送 谷氨酸能投射到plPFC，也接受来自plPFC的相互谷氨酸能输入。vbl.使用 光遗传投射打靶技术与plPFC细胞的逆行标记相结合，我们获得了两者 输入plPFC的特异性，以及投射到BLA的plPFC细胞输出的特异性。为了 了解ECB信号在BLA中对应激诱导的精神病理的缓冲作用 PlPFC回路，我们开发了一种行为模型，将小鼠分为应激敏感和应激- 适应力强的群体。目前的提案旨在回答两个关键的开放问题：欧洲央行是否发出信号 BLA-plPFC回路代表了一种能钝化应激诱导的行为病理的弹性因子？我们能不能 通过破坏BLA-plPFC相互作用回路中的ECB信号来实验诱导应激敏感性？ 利用最先进的病毒介导的基因转移方法和有条件的基因敲除动物，我们的目标是 了解BLA-plPFC回路中ECB信号在赋予应激弹性中的作用。这些 实验是第一次研究ECB信号在谷氨酸能相互回路中的作用。这将是 提高对焦虑和情绪障碍的病理生理学的理解，以及揭示一个假定的 大麻素激动剂抗焦虑作用的靶点。这项建议也构成了严格的技术 培训计划，其中我将学习和完善与立体定向手术，全细胞电生理学， 免疫组织化学和动物行为。

PROJECT SUMMARY Stress exposure is ubiquitous risk factor for the development of negative emotional states and neuropsychiatric disorders such as anxiety, depression, and post-traumatic stress disorder (PTSD). However, a causal link between stress-induced neuropathologies and resultant pathological behavioral states remains elusive. There is significant evidence to suggest that stress induces a wide variety of morphological and neurochemical adaptions in the prelimbic component of the medial prefrontal cortex (plPFC), a key nodal structure that is highly implicated in the top down regulation of emotional behavior. Indeed, susceptibility to the depressive effects of traumatic stress exposure is correlated with synaptic potentiation within this region. Interestingly, the anxiolytic effects of cannabinoid compounds are primarily mediated by activation of CB1 receptors on glutamatergic axon terminals within the mPFC. Stress itself dynamically alters endocannabinoid (eCB) signaling within the mPFC, as stress exposure induces a dramatic increase in levels of the EC ligand 2- AG in the mPFC, which is purported to represent an adaptive coping response that buffers against the negative physiological effects induced by stress exposure. However, it is completely unknown what neural pathways are modulated by eCBs to elicit this buffering effect on stress-induced behavioral pathologies. In our studies, we are looking at the projections to the plPFC from the Basolateral Amygdala (BLA), a brain region that has been highly implicated in the pathophysiology of affective disorders and PTSD. The BLA sends glutamatergic projections to the plPFC, and also receives reciprocal glutamatergic input from the plPFC. Using optogenetic projection targeting techniques combined with retrograde labeling of plPFC cells, we gain both specificity of input to the plPFC but also specificity of output of plPFC cells projecting to the BLA. In order to understand the role that eCB signaling plays in buffering against stress induced psychopathologies in the BLA- plPFC circuit, we have developed a behavioral model that separates mice into stress-susceptible and stress- resilient groups. The current proposal will aim to answer two critical open questions: Does eCB signaling in the BLA-plPFC circuit represent a resiliency factor that blunts stress-induced behavioral pathology? Can we experimentally induce stress susceptibility by impairing eCB signaling within BLA-plPFC reciprocal circuits? Using state of the art viral mediated gene transfer approaches and conditional gene knockout animals, we aim to understand the role of eCB signaling within the BLA-plPFC circuits in conferring resiliency to stress. These experiments represent the first investigation of eCB signaling in a reciprocal glutamatergic circuit. This will enhance are understanding of the pathophysiology of anxiety and mood disorders, as well as reveal a putative target for the anxiolytic effects of cannabinoid agonists. This proposal also constitutes a rigorous technical training plan, in which I will learn and refine skills related to stereotaxic surgery, whole-cell electrophysiology, immunohistochemistry, and animal behavior.