MECHANISMS OF CSD-EVOKED PERSISTENT ACTIVATION OF MENINGEAL NOCICEPTORS

CSD 诱发脑膜伤害感受器持续激活的机制

• 批准号: 9767291
• 负责人: DAN LEVY
• 金额: $ 41.05万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-15 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9767291
• 关键词: Acute; Affect; Afferent Neurons; Animals; Astrocytes; Auras; Behavior; Behavioral; Biological Process; Biosensor; Calcium; Cephalic; Chronic; Classic Migraine; Common Migraine; Conflict (Psychology); Data; Dichloromethylene Diphosphonate; Disease; Electrophysiology (science); Event; Exhibits; Fluoroacetates; Genetic; Grant; Headache; Hour; Image; Lead; Light; Link; Liposomes; Locomotion; Measures; Mechanics; Mediating; Meningeal; Meninges; Microelectrodes; Migraine; Molecular; Monitor; Mus; Naproxen; Nerve Endings; Neuropharmacology; Nociception; Nociceptors; Pain; Peripheral; Pharmacology; Phase; Play; Purinoceptor; Receptor Signaling; Rodent Model; Role; Sensory; Sex Differences; Signal Transduction; Spreading Cortical Depression; Stretching; Structure; Testing; Transgenic Mice; Trigeminal System; afferent nerve; awake; combat; disability; experimental study; imaging approach; in vivo; inhibitor/antagonist; innovation; insight; macrophage; new therapeutic target; novel; optogenetics; pain behavior; receptor; response; sensory system; theories; two-photon

Migraine is the second leading cause of disability worldwide; however, it remains unclear how the headache phase is initiated during a migraine attack. In migraine with aura, a condition that affects about 30% of people with migraine, the leading theory proposes that (a) cortical spreading depression (CSD) is the pathophysiological event that underlies the aura phase, and b) CSD somehow leads to the activation of the meningeal sensory system, resulting in the onset of the headache. Our recent studies, including during the prior grant period, provided a long-missing critical piece of support for the theory by finally showing that CSD does in fact activate meningeal sensory afferents, and can produce a prolonged period of both activation and mechanical sensitization. However, a long-standing problem with the CSD theory has been the paucity of evidence that CSD leads to pain behaviors, as would be expected for an event that supposedly is a potent trigger for headache. Furthermore, efforts to establish a link between CSD, the ensuing meningeal afferent responses, and headache pain have been limited by the challenges of studying the activity of meningeal sensory neurons in awake behaving animals. We have overcome this major obstacle by developing a two- photon calcium imaging approach to monitor the activity of meningeal afferent nerve endings in the awake behaving mouse, during voluntary locomotion via a chronic cranial window. In Aim 1, we propose to pursue this novel imaging approach to expand upon preliminary data suggesting that as a result of CSD-induced mechanical sensitization, meningeal stretching during voluntary locomotion results in enhanced activation of meningeal afferents, and consequent reduction of locomotion. Aims 2 and 3 are to explore cellular and molecular mechanisms that contribute to meningeal nociception following CSD. We will build upon preliminary results and use electrophysiology in anesthetized animals, calcium imaging in awake mice and an optogenetic approach to test the hypothesis that cortical astrocytes play a causal role in mediating the enhanced meningeal afferent responses and related decrease in voluntary locomotion following CSD. We will then employ biosensors, electrophysiology, afferent calcium imaging, pharmacological inhibitors and transgenic mice to test the hypothesis that astrocyte-dependent cortical ATP efflux contributes to CSD-evoked meningeal nociception via purinergic P2X7 signaling in meningeal macrophages. These innovative experiments, in addition of establishing a novel powerful platform for studying the responses of meningeal afferents and associated behavioral consequences related to migraine headache, could also shed light on the roles of cortical astrocytes and meningeal purinergic signaling, as well as sex differences in the mechanisms responsible for migraine pain - a key step towards mitigating the painful effects of CSD in migraine with aura.

偏头痛是全球残疾的第二大主要原因。但是，尚不清楚如何头痛 阶段是在偏头痛攻击期间开始的。在带有光环的偏头痛中，这种情况影响了约30％的人 与偏头痛有关，主要理论提出（a）皮质扩散抑郁症（CSD）是 基于光环阶段的病理生理事件，b）CSD以某种方式导致激活 脑膜感觉系统，导致头痛的发作。我们最近的研究，包括在 以前的赠款期，通过最终表明CSD提供了对理论的长期关键支持 实际上，确实会激活脑膜感觉传递物，并且可以产生长时间的激活和 机械敏化。但是，CSD理论的一个长期存在的问题是很少 CSD会导致疼痛行为的证据，正如据说是有效的事件所期望的那样 触发头痛。此外，为随后的脑膜传入而建立CSD之间建立联系的努力 反应和头痛疼痛受到研究脑膜活动的挑战的限制 醒着的动物中的感觉神经元。我们通过发展两个 光子钙成像方法以监测清醒中脑膜传入神经末端的活性 行为小鼠，在自愿运动期间通过慢性颅窗。在AIM 1中，我们建议追求这一点 新的成像方法扩展了初步数据，表明CSD诱导的结果 机械敏化，自愿运动期间的脑膜拉伸导致增强的激活 脑膜传入，并减少运动。目标2和3是探索细胞和 CSD后有助于脑膜伤害感受的分子机制。我们将基于初步 结果并在麻醉动物中使用电生理学，醒目小鼠的钙成像和光遗传学 测试皮质星形胶质细胞在介导增强脑膜中起因果作用的假设的方法 CSD后自愿运动的传入反应和相关的减少。然后我们将雇用 生物传感器，电生理学，传入钙成像，药理学抑制剂和转基因小鼠进行测试 星形胶质细胞依赖性皮质ATP外排有助于CSD诱发的脑膜伤害受伤的假设 通过脑膜巨噬细胞中的嘌呤能P2X7信号传导。这些创新的实验除了 建立一个新颖的强大平台，用于研究脑膜传入的反应和相关的反应 与偏头痛有关的行为后果，也可能阐明皮质星形胶质细胞的作用 和脑膜嘌呤能信号，以及负责偏头痛机制的性别差异 痛苦 - 缓解CSD在偏头痛中使用光环的痛苦影响的关键一步。