HIPPOCAMPAL SYNAPTIC STRUCTURE--PHYSIOLOGY DURING AGING

描述（改编自申请人的摘要）：这是一个提案， 一个关于基本膜和突触的项目的竞争性继续 大脑老化的机制已经持续了15年。 过去 在这个项目中，发现了两个主要的电生理变化 在大鼠海马CA 1区神经元中：1）突触频率受损 增强（促进）;和2）电压门控Ca 2+增加 流入。 这些结果和其他结果有助于一般的Ca 2 + 脑老化和痴呆假说。 最近一段时间， 单通道膜片钳配置适用于脑老化研究 并确定了可利用的L-型Ca 2+的膜密度增加， 通道作为一个潜在的分子基础的变化，随着年龄的增长， 细胞水平。 在这里，具体的假设，即增加L型钙通道是一个 受损功能（突触增强或尖峰）中关键机制 代）和衰老哺乳动物神经元的神经元死亡脆弱性 会得到考验 研究将在大鼠海马切片中进行， 长期海马培养，其中L型Ca 2+通道富集。 重复性突触激活对海马CA 1区神经元数量和分布的影响 成年和老年大鼠海马脑片神经元中的Ca 2+瞬变将被 研究，使用快速紫外兼容共聚焦激光扫描显微镜， Ca 2+成像与细胞内电生理同时进行 录制. 多种特异性通道阻断剂和激酶调节剂将被 用于定义关键的Ca 2+进入途径。 这些研究将决定 是否突触后钙瞬变，特别是通过L-通道， 调节神经元短期突触可塑性， 在老化的大脑神经元中。 在细胞培养的平行研究中， 将通过以下方法测试细胞死亡中的时间依赖性离子通道变化： 研究细胞对兴奋性毒性的脆弱性的差异， L型通道的不同补充。 单通道记录，Ca 2 + 将使用成像、药物阻断和激酶调节来确定 Ca 2+来源对坏死和凋亡至关重要。

DESCRIPTION (Adapted from applicant's abstract): This is a proposal for a competitive continuation of a project on basic membrane and synaptic mechanisms of brain aging that has been ongoing for over 15 years. The past periods in this project have found two main electrophysiological alterations in rat hippocampal CAl neurons with aging: 1) impaired synaptic frequency potentiation (facilitation); and 2) an increase in voltage-gated Ca2+ influx. These results and others have contributed to the general Ca2+ hypothesis of brain aging and dementia. In the most recent period, the single channel patch clamp configuration was adapted for brain aging studies and identified an increase in the membrane density of available L-type Ca2+ channels as a potential molecular basis for the changes with aging seen at the cellular level. Here, the specific hypothesis that the increase in L-type Ca2+ channels is a key mechanism in both impaired function (synaptic potentiation or spike generation) and neuronal vulnerability to death of aged mammalian neurons will be tested. Studies will be conducted in rat hippocampal slices and long-term hippocampal cultures in which L-type Ca2+ channels are enriched. Effects of repetitive synaptic activation on the magnitude and topography of Ca2+ transients in hippocampal slice neurons of adult and aged rats will be studied, using a rapid UV-compatible confocal laser scanning microscope for Ca2+ imaging simultaneously with intracellular electrophysiological recording. Multiple specific channel blockers and kinase modulators will be used to define critical Ca2+ entry pathways. These studies will determine whether postsynaptic Ca2+ transients, particularly through L-channels, can modulate neuronal short-term synaptic plasticity and contribute to changes in aged brain neurons. In parallel studies of cell cultures, the role of time-dependent ion channel changes in cell death will be tested, by investigating differences in vulnerability to excitotoxicity in cells with different complements of L-type channels. Single channel recording, Ca2+ imaging, pharmacologic blockade and kinase modulation will be used to define Ca2+ sources critical for necrosis and apoptosis.