GABA Receptors and Hilar Neuron Survival in Epilepsy

项目摘要 齿状回门区神经元的缺失是脑内最一致的形态学发现之一， 患有颞叶癫痫的人和获得性癫痫的相关模型。肺门两大群 神经元经常受损，GABA能生长抑素中间神经元和谷氨酸能苔藓细胞。 尽管多年来对门神经元的兴趣，重要的问题仍然存在。为什么神经元如此容易受到 兴奋性毒性损伤怎么保护他们？损失和损失的功能影响是什么？ 保存这些神经元的亚群？一套新的技术、试剂和小鼠现在将允许 以令人兴奋的新方式探索这些问题。拟议的研究将使用具有Cre重组酶的小鼠 在这些神经元中表达，以通过Cre激活的病毒基因表达选择性地操纵它们。一 将使用光镜和电镜免疫组织化学方法的组合来评估 变化和功能相关性将用电生理学方法确定。总体目标是 为了确定在这些神经元中增加的紧张性GABA能抑制是否具有神经保护作用， 一组单独的研究，以绘制功能电路，激活后，操纵苔藓或 细胞或生长抑素神经元在体内正常和易患癫痫的动物。具体目标1将测试 两组门神经元均缺乏GABAA受体亚单位的大量表达的假设 （GABAAR），并具有低水平的紧张性抑制。具体目标2将检验表达一个 外源性GABAAR亚单位，通常参与小脑的紧张性抑制，将导致 功能性GABAA受体的形成，并增加两组门神经元中的紧张性抑制。具体 目的3将检验增加肺门神经元的紧张性抑制将保护它们免受损伤的假设 癫痫持续状态之后具体目标4将检查在体内的门神经元的功能电路，通过使用 光遗传学方法选择性操纵神经元，然后通过Fos鉴定激活的神经元 标签。将比较正常和易患癫痫的动物中的激活模式，以测试 假设在体内刺激剩余的苔藓细胞或沉默剩余的生长抑素中间神经元将 导致癫痫小鼠中颗粒细胞活化增加。通过选择性操作肺门 神经元在完整的大脑，这些研究将提供其功能的独特看法，在正常和改变 神经回路

Project Summary Loss of neurons in the hilus of the dentate gyrus is one of the most consistent morphological findings in humans with temporal lobe epilepsy and related models of acquired epilepsy. Two major groups of hilar neurons are frequently damaged, GABAergic somatostatin interneurons and glutamatergic mossy cells. Despite years of interest in hilar neurons, important questions persist. Why are the neurons so vulnerable to excitotoxic damage? How could they be protected? What are the functional effects of both loss and preservation of subgroups of these neurons? A set of new technologies, reagents and mice will now allow probing these questions in exciting new ways. The proposed studies will use mice with Cre-recombinase expression in these neurons to selectively manipulate them through Cre-activated viral gene expression. A combination of light and electron microscopic immunohistochemical methods will be used to evaluate the changes, and functional correlates will be determined with electrophysiological methods. The broad goals are to determine if increasing tonic GABAergic inhibition in these neurons could be neuroprotective and, in a separate set of studies, to map the functional circuits that are activated following manipulation of either mossy cells or somatostatin neurons in normal and seizure-prone animals in vivo. Specific Aim 1 will test the hypothesis that both groups of hilar neurons lack substantial expression of the ¿ subunit of the GABAA receptor (GABAAR) and have low levels of tonic inhibition. Specific Aim 2 will test the hypothesis that expressing an exogenous GABAAR subunit, which is normally involved in tonic inhibition in the cerebellum, will lead to the formation of functional GABAA receptors and increase tonic inhibition in both groups of hilar neurons. Specific Aim 3 will test the hypothesis that increasing tonic inhibition in hilar neurons will protect them from damage following status epilepticus. Specific Aim 4 will examine the functional circuitry of hilar neurons in vivo by using optogenetic methods to manipulate the neurons selectively and then identifying the activated neurons by Fos labeling. The patterns of activation in normal and seizure-prone animals will be compared to test the hypotheses that stimulating remaining mossy cells or silencing remaining somatostatin interneurons in vivo will lead to increased granule cell activation in the epileptic mice. By allowing selective manipulation of hilar neurons in the intact brain, these studies will provide unique views of their function within normal and altered neuronal circuits.