GLUTAMATE-GATED CHANNELS IN CENTRAL & PERIPHERAL NEURONS

我工作的长期目标是让人们更好地了解 研究NMDA、AMPA和海人藻酸在突触传递中的作用 受体，形成由神经递质控制的离子通道 谷氨酸。另一个主要目标是揭示这些受体的特性 这可能允许临床干预以防止兴奋性毒性细胞 死亡。本提案中概述的实验侧重于功能 海人藻酸受体的特性。这种谷氨酸受体亚型是 被认为调节神经元的兴奋性，并可能有助于 在某些条件下的兴奋性毒性；但是，目前知道的要少得多 与NMDA和AMPA受体相比，海人藻酸受体的作用更强。膜片钳 将使用技术来记录全小区添加单通道 兴奋性氨基酸在分离的神经元上诱发的电流 天然谷氨酸受体，以及在表达克隆的异种细胞中 谷氨酸受体亚基。红藻氨酸受体的特征将是 尊重其激动剂和拮抗剂的药理、脱敏作用 性质、电流-电压关系、对钙的相对渗透性 和单价离子，以及对调制的敏感性。以进行实验 中枢神经系统神经元、NMDA和AMRA受体将被非 竞争性拮抗剂MK-801和GYKI 53655。 这项研究的第二个主要目的是检验红藻氨酸的假设 受体调节突触传递。红藻氨酸最初的作用 将在海马神经元生长形成的突触上进行研究 微培养。在初步实验中，激动剂红藻氨酸和 已经证明软骨藻酸盐既能抑制兴奋性又能抑制抑制性 突触。这种抑制的可能机制将是 将被详细审查。我们将寻求确定这一行动是否 涉及突触前或突触后红藻氨酸受体以及它们是否 与这些细胞中介导红藻氨酸电流的受体相同。 此外，我们将寻求确定在什么条件下 受体可能被内源性激动剂谷氨酸激活。

The long term objective of my work is to provide a better understanding of synaptic transmission by studying the operation of NMDA, AMPA, and kainate receptors, which form ion channels gated by the neurotransmitter glutamate. Another major goal is to uncover properties of these receptors that may allow for clinical intervention to prevent excitotoxic cell death. The experiments outlined in this proposal focus on the functional properties of kainate receptors. This glutamate receptor subtype is thought to regulate neuronal excitability and may contribute to excitotoxicity under certain conditions; but, currently much less is known about kainate receptors than about NMDA and AMPA receptors. Patch clamp techniques will be used to record the whole-cell add single channel currents evoked by excitatory amino acids in isolated neurons that express native glutamate receptors, and in heterologous cells that express cloned glutamate receptor subunits. Kainate receptors will be characterized with respect to their agonist and antagonist pharmacology, desensitization properties, current-voltage relations, relative permeability to calcium and monovalent ions, and susceptibility to modulation. For experiments on CNS neurons, NMDA and AMRA receptors will be blocked with the non- competitive antagonists MK-801 and GYKI 53655, respectively. A second major aim of this study is to test the hypothesis that kainate receptors regulate synaptic transmission. The action of kainate initially will be studied on synapses formed by hippocampal neurons grown in microcultures. In preliminary experiments, the agonists kainate and domoate have been shown to inhibit both excitatory and inhibitory synapses. The possible mechanisms that may underlie this inhibition will be examined in detail. We will seek to establish whether this action involves pre or postsynaptic kainate receptors and whether they are identical to the receptors that mediate kainate currents in these cells. In addition, we will seek to determine the conditions under which kainate receptors may be activated by the endogenous agonist, glutamate.