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: 10165837
• 负责人: DAN LEVY
• 金额: $ 30.85万
• 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/10165837
• 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; 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原因;然而，目前仍不清楚头痛是如何引起的。 阶段是在偏头痛发作期间开始的。在有先兆的偏头痛中， 对于偏头痛，主要的理论提出：（a）皮质扩散性抑制（CSD）是偏头痛的主要原因。 B）CSD以某种方式导致了先兆阶段的病理生理事件的激活， 脑膜感觉系统，导致头痛的发作。我们最近的研究，包括 前一个赠款期，提供了一个长期失踪的关键支持的理论，最终表明，CSD 事实上激活脑膜感觉传入，并能产生长时间的激活和 机械敏化然而，CSD理论的一个长期存在的问题是缺乏 证据表明，CSD导致疼痛行为，正如预期的事件，据说是一个强大的 头痛的诱因此外，努力建立CSD之间的联系，随后的脑膜传入 反应和头痛受到研究脑膜炎活动的挑战的限制， 清醒行为动物的感觉神经元。我们克服了这一重大障碍，制定了两个- 清醒状态下应用光子钙成像技术监测脑膜传入神经末梢的活动 行为小鼠，通过慢性颅窗自主运动期间。在目标1中，我们建议实现这一目标 一种新的成像方法，以扩大初步数据表明，由于CSD诱导的 机械致敏，自愿运动期间脑膜拉伸导致增强激活 脑膜传入神经，以及随之而来的运动减少。目标2和3是探索细胞和 分子机制，有助于脑膜伤害性感受后CSD。我们将建立在初步的 结果和应用麻醉动物的电生理学，清醒小鼠的钙成像和光遗传学 一种检验皮质星形胶质细胞在介导增强的脑膜炎中起因果作用的假设的方法。 传入反应和相关的减少自愿运动后CSD。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CSC诱发的脑膜伤害性感受的假设 通过脑膜巨噬细胞中的嘌呤能P2 X7信号传导。这些创新的实验，除了 建立一个新的强大的平台，研究脑膜传入和相关的反应， 与偏头痛相关的行为后果，也可以阐明皮质星形胶质细胞的作用， 和脑膜嘌呤能信号，以及偏头痛机制的性别差异 疼痛-减轻CSD对有先兆偏头痛的疼痛影响的关键一步。