Trans-synaptic signaling complex in amygdala pain mechanisms

总结： 疼痛是一个严重的临床问题，影响超过1亿美国人。痛苦的经济代价 据估计，包括医疗费用和生产力损失在内，损失超过数千亿美元。持久性 疼痛可能造成长期残疾，并导致抑郁、焦虑和认知障碍的加剧。 目前用于慢性疼痛的药物并不总是有效的，并且在耐受性和滥用方面存在局限性 责任。因此，确定新的治疗靶点对于解决这一临床负担至关重要。外周和中枢 已经鉴定出编码、传递和放大或减少疼痛信号的通路，包括脊髓丘脑和 脊臂旁神经通路脊旁臂-杏仁核内沿着关键节点的突触可塑性 该通路在疼痛调节和从亚急性疼痛向慢性疼痛的转变中起重要作用。但 控制该系统的发育、维持和可塑性的机制及其在疼痛持续性中的作用 行为仍然知之甚少。这项研究将推进跨突触信号传导的概念， 以谷氨酸δ 1受体为中心的复合体调节中枢侧囊区突触的功能 杏仁核也称为“伤害感受性杏仁核”，并且有助于持续性疼痛机制。具体目标1将 确定这些受体的细胞类型和投射特异性分布及其在调节杏仁核回路中的作用 以及正常情况下的伤害反应和厌恶情绪行为。具体目标2将确定持续性/慢性 使用炎性和神经性疼痛模型研究谷氨酸δ 1信号传导的疼痛相关变化，并测试 疼痛模型中突触神经可塑性的拯救策略。痛时杏仁核突触超微结构的变化 将使用3D电子显微镜对模型进行评价。具体目标3将确定恢复反式- 通过谷氨酸δ 1受体的突触信号传导减轻疼痛中的伤害性和厌恶性情感行为 模型补充实验将解决中央杏仁核的细胞类型特异性操纵的影响 减轻疼痛的电路。为了实现这些目标，我们将利用脑切片电生理学， 行为，化学和光遗传学，共聚焦和电子显微镜（免疫和3D），以及遗传方法， 确定谷氨酸δ 1信号复合物调节的功能和结构机制 疼痛相关的神经可塑性和行为。这个项目意义重大，因为它将确定一种新的大脑机制， 可以作为疼痛管理的目标。研究设计的科学严谨性是通过使用多个 方法和途径，在独立实验室重复实验，使用经验证的模型和试剂， 除实验设计的其他方面外，还应考虑设盲、生物学变量和性别。

Summary: Pain is a serious clinical problem that affects more than 100 million Americans. The economic costs of pain have been estimated to be more than several hundred billion dollars including healthcare costs and lost productivity. Persistent pain may produce long-term disability and lead to precipitation of depression, anxiety and cognitive impairment. Currently used medications for chronic pain are not always effective and have limitations in terms of tolerance and abuse liability. Thus, identifying novel therapeutic targets is essential to address this clinical burden. Peripheral and central pathways that encode, transmit, and amplify or reduce pain signals have been identified, including the spinothalamic and spinoparabrachial pathways. Plasticity of glutamatergic synapses along key nodes in the spinoparabrachial-amygdala pathway plays an important role in pain modulation and in the transition from subacute to chronic pain. However, the mechanisms governing the development, maintenance and plasticity of this system and their role in persistence of pain behaviors remain poorly understood. The proposed research will advance the concept that the trans-synaptic signaling complex centered on glutamate delta 1 receptor regulates function of synapses in the laterocapsular region of central amygdala also known as “nociceptive amygdala” and contributes to persistent pain mechanisms. Specific Aim1 will define the cell type- and projection-specific distribution of these receptors and their role in regulating amygdala circuitry and nocifensive and averse-affective behavior under normal conditions. Specific Aim 2 will determine persistent/chronic pain-related changes in glutamate delta 1 signaling using inflammatory and neuropathic pain models and test the effect of a rescue strategy on synaptic neuroplasticity in pain models. Changes in ultrastructure of amygdala synapses in pain models will be evaluated using 3D-electron microscopy. Specific Aim 3 will determine the effect of restoring trans- synaptic signaling through the glutamate delta 1 receptor in mitigating nocifensive and averse-affective behaviors in pain models. Complementary experiments will address the effect of cell-type specific manipulation of central amygdala circuitry in mitigating pain. To accomplish these aims we will utilize a combination of brain slice electrophysiology, behavior, chemo- and opto-genetics, confocal and electron microscopy (immuno and 3D), and genetic approaches to determine the functional and structural mechanisms through which the glutamate delta 1 signaling complex regulates pain-related neuroplasticity and behaviors. This project is significant because it would identify a novel brain mechanism of pain that could be targeted for pain management. Scientific rigor of research design is established by the use of multiple methods and approaches, replication of experiments in independent laboratories, use of validated models and reagents, consideration of blinding, biological variables and sex in addition to other aspects of experimental design.