AMPA/Kainate Receptors, Free Radicals, And Motor Neuron Injury

肌萎缩侧索硬化症患者脑脊液谷氨酸升高的观察，以及运动神经元(MN) 选择性易受谷氨酸受体介导的(“兴奋性毒性”)损伤支持兴奋性毒性贡献 到MN在疾病中的损失。过去的研究强调了可能导致这种脆弱性的因素；在 与大多数其他神经元相比，兴奋性激活mns可引起更大的线粒体钙超载 以及异常强烈的活性氧(ROS)生成。然而，虽然星形胶质谷氨酸 转运蛋白是CMS摄取谷氨酸的主要原因，它们的损害似乎是基础 在ALS中，细胞外谷氨酸升高，其功能障碍的原因尚不清楚。提供一个 可能的线索，最近的研究表明，这种ROS在MNS内产生，以回应兴奋性毒性 激活本身可能会扰乱周围星形胶质细胞对谷氨酸的摄取。这些观察结果 提出一种将兴奋性MN损伤与谷氨酸氧化破坏联系起来的机制 运输，并为ALS的前馈模型提供基础，在该模型中，一系列激发因素 可能导致一种常见的疾病途径。 这项建议的广泛目标是使用文化和切片模型来扩展这些研究并进一步 检验MNS内ROS的产生有助于局部谷氨酸损失的假设 体内转运。MNS内激发毒性ROS的产生及其穿透周围组织和 阻断谷氨酸转运将在分离和切片培养模型中进行检验，这些模型来自野生型小鼠AS 以及携带与家族性肌萎缩侧索硬化症相关的超氧化物歧化酶(SOD)突变的小鼠(这是 提供最好的疾病动物模型)。超氧化物歧化酶突变小鼠将被用来检测 哪些氧化变化和运输中断发生在紧邻大腹侧的区域 角MN，如果MN是ROS的来源，就会被预测。最后，选拔的能力 减少这些病理过程的药物干预将在切片和动物身上进行测试 模特们。希望这些研究将进一步澄清最终导致选择性MN的事件序列 在肌萎缩侧索硬化症中的损失，从而促进新的治疗策略的开发。

Observations of increased CSF glutamate in ALS, together with findings that motor neurons (MNs) are selectively vulnerable to glutamate receptor mediated ("excitotoxic") injury support an excitotoxic contribution to MN loss in the disease. Past studies have highlighted factors that may underlie this vulnerability; in comparison to most other neurons, excitotoxic activation of MNs induces greater mitochondrial Ca2+ overload and exceptionally strong reactive oxygen species (ROS) generation. However, while astroglial glutamate transporters account for most glutamate uptake in the CMS,and their damage appears to underlie extracellular glutamate elevations in ALS, the reason for their dysfunction has been unclear. Providing a possible clue, recent studies suggest that this ROS generated within MNs in response to excitotoxic activation may in itself cause disruption of glutamate uptake in surrounding astrocytes. These observations suggest a mechanism that causatively links excitotoxic MN damage with oxidative disruption of glutamate transport, and provide the basis the for a feed forward model of ALS, in which a range of inciting factors could lead into a common disease pathway. The broad aim of this proposal is to use culture and slice models to extend these studies and further examine the hypothesis that ROS generation within MNs contributes to the loss of regional glutamate transport in vivo. Excitotoxic ROS generation within MNs and its ability to penetrate surrounding tissue and disrupt glutamate transport will be examined in dissociated and slice culture models from wild type mice as well as mice harboring superoxide dismutase (SOD) mutations associated with familial forms of ALS (which provide the best animal models of the disease). SOD mutant mice will be used to examine the degree to which oxidative changes and disruption of transport occurs in regions immediately surrounding large ventral horn MNs, as would be predicted if the MNs are the source of the ROS. Finally, the ability of selected pharmacological interventions to decrease these pathological processes will be tested in slice and animal models. It is hoped that these studies will further clarify sequences of events culminating in selective MN loss in ALS, and thereby facilitate development of new treatment strategies.