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Purkinje Cell Rhythmicity, Synchrony, and Enhancing Function in Cerebellar Disorders

小脑疾病中浦肯野细胞的节律性、同步性和增强功能

基本信息

批准号：
10337182
负责人：
JOHN SAMUEL STAHL
金额：
--
依托单位：
LOUIS STOKES CLEVELAND VA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10337182
关键词：
4-Aminopyridine Abnormal coordination Address Affect Aging Alcohol abuse Alcoholism Aminopyridines Animals Anterior Area Bathing Behavior Behavioral Biological Assay Blast Injuries Blurred vision Brain Stem Calcium Channel Cerebellar Diseases Cerebellar vermis structure Cerebellum Chronic Clinic Code Conflict (Psychology)Data Disease Dizziness Dose Engineering Equilibrium Exposure to Eye Movements Fire - disasters Functional disorder Gait Genes Genetic Diseases Goals Human In Vitro Ions Knowledge Laboratories Literature Mouse Strains Mus Mutation Neurodegenerative Disorders Neurologist Neurology Oral Pacemakers Patients Pattern Performance Periodicity Pharmaceutical Preparations Physiology Property Publishing Purkinje Cells Reflex control Reflex eye movement Route Signal Transduction Stimulus Stroke Symptoms Synapses Technology Testing Time Trauma Tremor Variant Veterans Vision Visual impairment Work awake cell motility design drug development effectiveness evaluation experimental study falls improved improved functioning in vitro Assay in vivo laboratory equipment military veteran neurophysiology optogenetics patient subsets stem success theories transmission process

项目摘要

Because there are so many causes of cerebellar damage (e.g. alcoholism, blast injury, neurodegenerative diseases, stroke, and simple aging), veterans suffering imbalance, visual impairment, and incoordination due to cerebellar damage are common. In the past, neurologists had few therapies to improve function in these patients. Now two emerging ideas in cerebellar physiology hold the promise that better treatments can be rationally designed. The irregularity hypothesis states that cerebellar dysfunction arises when cerebellar Purkinje cells (PCs) fire in irregular patterns through loss of their pacemaker properties. It is cited to explain why drugs that increase PC rhythmicity in vitro such as 4-aminopyridine (4-AP) improve certain manifestations of cerebellar disease in mice and humans, and it predicts their usefulness in a wide range of cerebellar disorders. The PC synchrony hypothesis states that synchrony of firing across multiple PCs determines the effectiveness with which PCs control their synaptic targets, and may explain why PC irregularity – which could disrupt PC synchrony – is deleterious. If correct, these hypotheses indicate how laboratory assays can be used to develop more tolerable and effective drugs. If incorrect, their application to drug development will be futile. Currently, both hypotheses are unproven, and there are data challenging the applicability of the theory to the flocculus and other regions of the vestibulocerebellum, even though it was work in the flocculus that led to the irregularity hypothesis in the first place. This project will address conflicting findings in the literatures on irregularity, 4-AP, and PC synchrony. Like much previous work on the irregularity hypothesis, parts of the proposal will be conducted in the ataxic mouse tottering (tg), which carries a mutation in Cacna1a, the gene encoding the ion pore subunit of the P/Q calcium channel. We focus on the flocculus and its control of reflex eye movements that maintain clear vision, because their physiology is well understood, because work in this area provides both support and challenges to the irregularity and synchrony hypotheses, because eye movement and related balance abnormalities contribute significantly to the symptoms of cerebellar disease, and because successes to date predict their treatment is possible. Specific Aim 1 will investigate why bath-applied 4-AP restores regularity of tg vermis PCs in vitro, and oral 4-AP improves tg's performance on the rotarod, but parenterally administered 4-AP does not improve tg's eye movement deficits that are attributed to flocculus dysfunction. We will test the possibilities that the conundrum arises through non-validity of the irregularity hypothesis, or through regional variations in cerebellar physiology, or through differing effects of chronic oral vs. short-term parenteral exposure to 4-AP. Specific Aim 2 addresses the idea that PC irregularity disrupts the PC-PC synchrony on which normal cerebellar function depends. We will test that explanation by determining whether PC synchrony is in fact reduced in tg. As in Aim 1, to address the possibility of regional variations of physiology, we will record in the flocculus and in a non- vestibulocerebellar region of the vermis. Specific Aim 3 addresses a prediction of the posited linkage between irregularity and PC synchrony: If these ideas apply to the flocculus, then variations in PC firing rate should drive eye movements more robustly when the PCs fire more synchronously. Making use of an optogenetic mouse strain whose PCs express channelrhodopsin, we will stimulate PCs with patterns of photostimulation predicted to trigger PC firing with varying degrees of synchrony. Through recordings of PC firing rates and eye movements, we will quantify and compare the efficiency with which flocculus signals are transferred to subsequent circuitry. The results of this proposal will have broad implications for the general validity of the irregularity hypothesis, the usefulness and limitations of in vitro regularity assays in drug development, and predicting which cerebellar disorders might respond to 4-AP.

因为导致小脑损伤的原因很多(如酒精中毒、冲击伤、神经退行性变疾病、中风和简单的衰老)，遭受失衡、视力障碍和协调不良的退伍军人由于小脑受损是常见的。在过去，神经科医生几乎没有改善功能的疗法。这些病人。现在，小脑生理学领域出现了两个新概念，它们承诺更好的治疗方法可以合理地设计。不规则性假说指出，小脑功能障碍出现在小脑浦肯野细胞(PC)由于失去起搏器的特性而以不规则的模式放电。它是被引用来解释为什么在体外增加PC节律性的药物，如4-氨基吡啶(4-AP)可以改善小脑疾病在小鼠和人类中的某些表现，它预测了它们在广泛的一系列小脑疾病。PC同步假说说明了在多个 PC决定了PC控制其突触靶标的有效性，并可能解释为什么PC 不规则性--可能会扰乱PC同步--是有害的。如果是正确的，这些假设表明了实验室化验可以用来开发更耐受、更有效的药物。如果不正确，他们的应用程序要开发药物将是徒劳的。目前，这两种假设都没有得到证实，而且有数据该理论对前庭小脑的小叶和其他区域的适用性提出了质疑，尽管最初是小叶的工作导致了不规则性假说。这该项目将解决关于不规则、4-AP和PC同步的文献中相互矛盾的发现。喜欢之前许多关于不规则假说的工作，部分提案将在共济失调中进行小鼠摇摇欲坠(Tg)，携带Cacna 1a突变，Cacna 1a基因编码 P/Q钙通道。我们关注的是小叶及其对维持眼球运动的反射性眼球运动的控制。清晰的视野，因为他们的生理很好地理解，因为在这一领域的工作提供了两个支持以及对不规则和同步性假说的挑战，因为眼球运动和相关的平衡异常对小脑疾病的症状有很大影响，而且由于治疗的成功日期预测他们的治疗是可能的。特定目标1将调查为什么使用BASH的4-AP恢复甘油三酯在体外的规律性，口服4-AP提高了甘油三酯在转杆上的性能，但非肠道注射4-AP不能改善TG的眼球运动缺陷，这些缺陷被归因于小叶功能障碍。我们将测试难题产生的可能性，因为不规则性假说，或通过小脑生理的区域差异，或通过不同的影响长期口服与短期非肠道接触4-AP的对比。《特定目标2》阐述了个人电脑不规则扰乱了正常小脑功能所依赖的PC-PC同步性。我们将对此进行测试通过确定PC同步性在TG中是否实际上降低来解释。如目标1所示，要解决生理区域变异的可能性，我们将记录在小叶和非小叶中蚯蚓的前庭小脑区。具体目标3解决了对假定的连锁的预测在不规则性和PC同步性之间：如果这些想法适用于小叶，那么PC激发的变化当PC同步启动时，Rate应该会更有力地驱动眼球运动。利用一种光遗传小鼠品系，其PC表达通道视紫红质，我们将用以下模式刺激PC 光刺激预计会以不同程度的同步性触发PC。通过录制 PC的放电率和眼球运动，我们将量化和比较信号被传输到后续电路。这项提议的结果将产生广泛的影响。对于不规则性假说的普遍有效性，体外规律性的有用性和局限性在药物开发中的分析，并预测哪些小脑疾病可能对4-AP有反应。