WHITE MATTER EXCITOTOXICITY

描述：（逐字来自申请人的摘要） 中枢神经系统的白色物质在 传输电信号。常见和毁灭性的疾病，如 中风、脊髓损伤和多发性硬化症几乎总是会对 白色物质的结构，但远不知道的病理生理学， 白色物质损伤。尽管在这个组织中缺乏突触机制， 早期的报道表明谷氨酸依赖性兴奋性毒性机制起作用， 在介导白色物质损伤中起重要作用。本申请旨在 更详细地研究内源性兴奋毒素如何损害有髓鞘的轴突。 利用离体大鼠视神经和脊髓背柱， 分离的白色物质模型，电生理学和免疫组化， 髓鞘、轴浆和神经胶质细胞质中的损伤标记物将用于检查 外源性兴奋性毒素如谷氨酸盐、海人藻酸盐和 阿尼帕选择性抑制剂将被应用于解剖出哪些亚类 离子型谷氨酸受体是损伤的原因。异常通量 将使用离子敏感染料和共聚焦显微镜检查Na和Ca离子 用显微镜观察哪些部分（髓鞘、轴突圆柱体、神经胶质）受损 谷氨酸受体激活导致的过量积累。共计（免费 + 结合）元素分析的Na和Ca将进行电子探针 X射线显微分析作为电离部分可能低估总量 Na或Ca进入，并可能是随后的更可靠的决定因素 功能性损伤非突触释放的内源性谷氨酸的作用 通过体外缺氧或缺血，将使用类似的方法进行研究， 确定哪些亚细胞区室遭受离子过载的目标 以及依赖于谷氨酸受体激活的结构损伤。 免疫组化和高分辨率共聚焦显微镜，加上 用于分辨率增强的数字图像处理技术， 3-三维重建，将被应用于检查的分布 用特异性抗血清检测白色物质中的谷氨酸受体。通过阐明 在中枢神经系统白色物质中谷氨酸依赖性损伤机制，希望 重要的新途径将可用于药理学保护， 这个关键组织

DESCRIPTION: (Verbatim from the Applicant's Abstract) Axonal connections within the white matter of the central nervous system play the crucial role of transmitting electrical signals. Common and devastating diseases such as stroke, spinal cord injury and multiple sclerosis almost always cause damage to white matter structures, yet far less is known about the pathophysiology of white matter injury. Despite the lack of synaptic machinery in this tissue, early reports indicate that glutamate-dependent excitotoxic mechanisms play an important role in mediating white matter injury. This application aims to examine in greater detail how endogenous excitotoxins damage myelinated axons. Using the in vitro rat optic nerve and spinal dorsal columns as well studied models of isolated white matter, electrophysiology and immunchistochemistry for injury markers in myelin, axoplasm and glial cytoplasm will be used to examine the effects of exogenously applied excitotoxins such as glutamate, kainite, and ANIPA. Selective inhibitors will be applied to dissect out which subclass of ionotropic glutamate receptor(s) are responsible for injury. Abnormal fluxes of Na and Ca ions will be examined using ion-sensitive dyes and confocal microscopy to see which compartments (myelin, axon cylinder, glia) suffer excess accumulations as a result of glutamate receptor activation. Total (free + bound) elemental analysis of Na and Ca will be performed with electron probe x-ray microanalysis as the ionized fraction may underestimate the total amount of Na or Ca entry and may be a more reliable determinant of subsequent functional injury. The role of endogenous glutamate, released non-synaptically by in vitro anoxia or ischemia, will be studied using a simlar approach, with the goal of determining which sub cellular compartments suffer ionic overload and structural injury that is dependent on activation of glutamate receptors. Immunchistochemistry and high-resolution confocal microscopy, coupled with digital image processing techniques for resolution enhancement and 3-dimensional reconstruction, will be applied to examine the distribution of glutamate receptors in white matter using specific antisera. By elucidating glutamate-dependent injury mechanisms in CNS white matter, it is hoped that an important new avenue wil1 become available for pharmacological protection of this key tissue.