WHITE MATTER EXCITOTOXICITY

描述：(逐字摘自申请者摘要)内轴突连接 中枢神经系统的白质起着至关重要的作用 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造成 白质结构，但对其病理生理学知之甚少。 脑白质损伤。尽管这个组织中缺乏突触机制， 早期报道表明，谷氨酸依赖的兴奋性毒性机制在 在调节脑白质损伤中的重要作用。此应用程序旨在 更详细地研究内源性兴奋性毒素是如何损害有髓轴突的。 用体外培养的大鼠视神经和脊髓背柱进行了研究 脑白质离体电生理学和免疫血吸虫化学模型 将使用髓鞘、轴浆和神经胶质细胞质中的损伤标志物来检查 外源应用兴奋性毒素，如谷氨酸、海藻氨酸和 阿尼帕。将应用选择性抑制剂来剖析出哪一子类 离子型谷氨酸受体(S)对损伤负有责任。不正常的流量 将使用离子敏感染料和共聚焦来检测Na和Ca离子 显微镜观察哪些隔室(髓鞘、轴突、神经胶质)受损 谷氨酸受体激活导致的过量蓄积。合计(免费 将用电子探针进行钠和钙的元素分析 X射线微量分析，因为电离部分可能低估了总量 钠或钙的进入，并可能是更可靠的决定因素 功能性损伤。内源性谷氨酸在非突触释放中的作用 通过体外缺氧或缺血，将使用类似的方法进行研究， 确定哪些亚细胞隔间遭受离子过载的目标 以及依赖于谷氨酸受体激活的结构性损伤。 免疫组织化学和高分辨率共聚焦显微镜，结合 分辨率增强的数字图像处理技术和 三维重建，将被应用于检查分布情况 使用特定抗血清检测白质中的谷氨酸受体。通过澄清 中枢神经系统白质谷氨酸依赖性损伤机制的研究 重要的新途径将成为可用于药物保护的 这个钥匙组织。

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.