Cerebellar malfunction and damage during ischemia

缺血期间的小脑功能障碍和损伤

• 批准号: 7033483
• 负责人: DAVID J ROSSI
• 金额: $ 33.18万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7033483
• 关键词: GABA receptor; apoptosis; biological signal transduction; brain electrical activity; calcium flux; cerebellar Purkinje cell; cerebellar disorders; confocal scanning microscopy; disease /disorder model; fluorescence microscopy; glutamate receptor; glutamate transporter; glutamates; granule cell; ischemia; laboratory rat; molecular pathology; mossy fiber; neural transmission; pathologic process; voltage /patch clamp

DESCRIPTION (provided by applicant): ' The primary goal of this proposal is to investigate mechanisms that may be involved in cerebellar damage and malfunction during brain ischemia. Brain ischemia, which occurs during cardiac arrest, stroke and perinatal asphyxia, is a leading cause of death and long term disability. The cerebellum is a frequent target of stroke, and cerebellar Purkinje cells are one of the most susceptible brain cells to ischemic damage. However, relatively little is known about how Purkinje cells respond to and are damaged by ischemia. This lack of information is problematic because many of the ischemic mechanisms operating in other brain regions involve molecular processes that are either not expressed or have an unusual configuration in Purkinje cells. For this proposal, a brain slice model will be used to simulate brain ischemia in vitro and patch-clamp recording, confocal fluorescence imaging and pharmacological manipulations will be used to investigate mechanisms of cerebellar ischemic damage. Simulated ischemia induces a severe depolarization of Purkinje cells which is mediated by activation of non-NMDA ionotropic glutamate receptors (and possibly other glutamate receptors/transporters) but its onset is delayed by activation of GABAA receptors. These electrophysiological responses are associated with extensive tissue swelling and the subsequent development of necrotic and apoptotic cell death very similar to that observed with in vivo models. Simulated ischemia also severely disrupts electrical signal transduction through the cerebellum and the disruption persists for long periods after the ischemic episode is terminated. Determining the mechanisms that underlie both cellular damage and disrupted signal processing should provide useful information for the development of therapies. The specific aims of this proposal are: 1) To determine the mechanisms that lead to glutamate accumulation around Purkinje cells, elucidate which receptors mediate the Purkinje cell response and determine their contribution to cell damage; 2) To determine the mechanisms by which GABAA receptor activation delays the onset of Purkinje cell depolarization and to determine if the delay is beneficial or damaging; and 3) To determine where in the cerebellar circuitry and by what mechanism electrical signal transduction is disrupted.

描述（由申请人提供）：“该提案的主要目标是研究可能涉及脑缺血期间小脑损伤和功能障碍的机制。心脏骤停、中风和围产期窒息期间发生的脑缺血是死亡和长期残疾的主要原因。小脑是中风的常见目标，小脑浦肯野细胞是最容易受到缺血性损伤的脑细胞之一。然而，人们对浦肯野细胞如何响应缺血以及如何受到缺血的损害知之甚少。这种信息的缺乏是有问题的，因为在其他大脑区域运作的许多缺血机制涉及浦肯野细胞中不表达或具有不寻常结构的分子过程。对于该提案，将使用脑切片模型来模拟体外脑缺血，并使用膜片钳记录、共聚焦荧光成像和药理学操作来研究小脑缺血损伤的机制。模拟缺血会诱导浦肯野细胞严重去极化，这是由非 NMDA 离子型谷氨酸受体（可能还有其他谷氨酸受体/转运蛋白）的激活介导的，但其发作会因 GABAA 受体的激活而延迟。这些电生理反应与广泛的组织肿胀以及随后的坏死和凋亡细胞死亡的发展有关，与体内模型观察到的情况非常相似。模拟缺血还会严重扰乱通过小脑的电信号转导，并且这种扰乱在缺血发作终止后仍会持续很长一段时间。确定细胞损伤和信号处理中断的机制应该为治疗的开发提供有用的信息。该提案的具体目标是：1）确定导致浦肯野细胞周围谷氨酸积累的机制，阐明哪些受体介导浦肯野细胞反应并确定它们对细胞损伤的贡献； 2) 确定GABAA受体激活延迟浦肯野细胞去极化发生的机制，并确定这种延迟是有益的还是有害的； 3) 确定小脑电路中的何处以及电信号转导被破坏的机制。