GLUTAMATE EXCITOTOXICITY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 谷氨酸兴奋性毒性是神经细胞死亡的重要介质，可能参与中风、癫痫和创伤性脑损伤的病理过程。长期谷氨酸暴露致神经元损伤的主要机制是通过NMDA谷氨酸受体进入细胞内，导致线粒体对细胞内钙离子的截留。这导致线粒体钙超载，ROS产生增加，生物能量学中断，细胞结构丧失。另一种理论认为，Ca~(2+)，甚至Na~+的积累可能会导致ATP消耗泵对ATP的需求增加，从而导致细胞内ATP的耗尽。ATP耗竭条件是细胞死亡的决定因素还是表现形式仍是一个问题。 与马特森实验室(NIA)合作，BRC的目标是评估单个海马神经元的氧气消耗，以便深入了解谷氨酸暴露期间线粒体的呼吸能力。最大耗氧量是临界ATP耗竭的良好指标，如在暴露于线粒体解偶联化合物时观察到的那样。在这项提议之前，仅对整个神经元群体的耗氧量进行了评估。这导致了一些问题，如药物的时间反应性以及对同质细胞群体的需求。随着自参照式氧气微传感器的发展，BRC能够在单细胞水平上测量氧通量，从而测量氧气消耗。通过将这项技术与共聚焦显微镜相结合，有望建立线粒体膜电位、细胞内钙离子和氧耗之间的时间关系，并为兴奋性毒性的潜在机制提供线索。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Glutamate excitotoxicity is an important mediator of neuronal cell death and may contribute to the pathology of stroke, epilepsy and traumatic brain injury. The chief mechanism of neuronal injury during prolonged glutamate exposure is due to Ca2+ entry through NMDA glutamate receptors and consequent sequestration of Ca2+ by mitochondria.. This leads to mitochondrial Ca2+ overload, increase in ROS production, disruption of bioenergetics and loss of cellular architecture. Alternative theories suggest that accumulation of Ca2+ and indeed Na+ may lead to an increase in ATP demand from ATP-consuming pumps and consequent depletion of intracellular ATP. It remains a question whether ATP depleting conditions are a determinant or a manifestation of cell death. In conjunction with the Mattson Laboratory (NIA), the BRC has aimed to assess oxygen consumption in single hippocampal neurons in order to gain insight into mitochondrial respiratory capacity during exposure to glutamate. Maximal oxygen consumption is a good indicator of critical ATP depletion, as observed during exposure to mitochondrial uncoupler compounds. Oxygen consumption has only been assessed in whole neuronal populations prior to this proposal. This leads to problems such as the time responsiveness to drugs as well as the need for a homogeneous population of cells. With the development of self-referencing oxygen microsensors, the BRC is able to measure oxygen flux and therefore oxygen consumption at the single cell level. By combining this technique with confocal microscopy, it is anticipated that temporal relationships between mitochondrial membrane potential, intracellular Ca2+ and oxygen consumption will be established and provide clues to the underlying mechanism of excitotoxicity.