Brain Circuits of Migraine Pain

总结 偏头痛是一种流行的神经系统疾病，影响着全世界数百万人。底层 偏头痛的病理生理学可能涉及三叉神经疼痛通路内的多种机制， 大脑中的相关结构。最近推出的针对CGRP机制的药物，包括 抗体和小分子CGRP受体拮抗剂似乎在血脑屏障外起作用。这些 药物作为预防性治疗在某些患者中是有效的，这暗示了脑膜CGRP在 偏头痛病理学然而，许多患者对这些疗法没有反应，甚至那些经常 经历“突破性偏头痛”，表明存在非CGRP外周性偏头痛机制。 调节偏头痛的大脑回路仍然研究不足。头部伤害感受通路包括 激活三叉神经传入和传递伤害性信号通过二级细胞在 trigeminocerebral complex（TCC）是一种多脑区的神经元。偏头痛发作期间的人类神经影像学研究 已经证实杏仁核和背侧脑桥的激活，包括臂旁核（PBN）。 PBN接收外感受性和内感受性感觉输入，并投射到多个部位，包括 杏仁核的中央核（CeA），是一个调节疼痛情绪的区域。我们的临床前研究 使用药理学和光遗传学激活硬脑膜传入，神经元追踪和行为表明， 从硬脑膜到TCC、PBN和CeA的功能通路可能促进偏头痛样疼痛。 在这项建议中，我们将使用光/化学遗传学方法，显微镜与免疫染色和RNA显微镜， CRISPR-Cas9（即，CRISPR）基因操作、电生理学、钙成像和疼痛行为， 研究PBN→CeA通路是否以及如何促进硬脑膜激活引起的偏头痛样疼痛。 在雄性和雌性小鼠中使用几种不同的方法进行传入。目标1将测量对标记物的影响 大脑网络中的神经激活（显微镜）和对疼痛行为的后果;目标2将使用大脑 切片电生理学和钙成像与药理学，CRISPR或光/化学遗传学 PBN输出的操作，以评估CeA细胞类型的可塑性;目标3将使用 PBN输出或CeA中的CRISPR缺失，以评估对偏头痛行为的可能抑制。 我们的研究旨在解决我们对偏头痛中枢通路的认识中的重大空白。我们将 确定中枢PBN→CeA回路作为偏头痛常见通路的潜在相关性， 可通过CGRP依赖性和CGRP非依赖性外周机制参与。

Summary Migraine is a prevalent neurological disorder affecting millions of people worldwide. The underlying pathophysiology of migraine likely involves diverse mechanisms within the trigeminal pain pathways and pain- related structures in the brain. Recently introduced medications targeting CGRP mechanisms including antibodies and small molecule CGRP receptor antagonists appear to act outside of the blood brain barrier. These medications are effective as preventive treatment in some patients implicating the role of meningeal CGRP in migraine pathology. However, many patients do not respond to these therapies and even those that do often experience “breakthrough migraines” suggesting the existence of non-CGRP peripheral migraine mechanisms. The brain circuits mediating migraine pain remain understudied. Cephalic nociceptive pathways involve activation of trigeminal afferents and transmission of the nociceptive signal through the second order cells in the trigeminocervical complex (TCC) to multiple brain regions. Human neuroimaging studies during a migraine attack have demonstrated activations in the amygdala and dorsal pons, encompassing the parabrachial nucleus (PBN). The PBN receives both exteroceptive and interoceptive sensory inputs and projects to multiple sites including the central nucleus of the amygdala (CeA), an area mediating emotional aspects of pain. Our preclinical studies using pharmacological and optogenetic activation of dural afferents, neuronal tracing and behavior suggest a functional pathway from the dura mater to TCC, PBN and CeA that may promote migraine-like pain. In this proposal, we will use opto/chemo-genetic methods, microscopy with immunostaining and RNAscope, CRISPR-Cas9 (i.e., CRISPR) genetic manipulations, electrophysiology, calcium imaging and pain behavior to investigate if, and how, the PBN→CeA pathway may promote migraine-like pain elicited by activation of dural afferents using several different approaches in male and female mice. Aim 1 will measure the effects on markers of neural activation in brain networks (microscopy) and consequences on pain behavior; Aim 2 will use brain slice electrophysiology and calcium imaging with pharmacological, CRISPR or opto/chemo-genetic manipulations of PBN outputs to evaluate plasticity of CeA cell types; Aim 3 will use chemogenetic inhibition of PBN outputs or CRISPR deletions in the CeA to evaluate possible inhibition of migraine pain behaviors. Our studies aim to address significant gaps in our knowledge of central pathways of migraine pain. We will determine the potential relevance of the central PBN→CeA circuit as a common pathway of migraine pain that can be engaged by CGRP-dependent and CGRP-independent peripheral mechanisms.