HIPPOCAMPAL SYNAPTIC STRUCTURE--PHYSIOLOGY DURING AGING

描述(改编自申请人的摘要)：这是一份关于 一个关于基膜和突触的竞争性延续项目 大脑老化的机制已经持续了15年以上。过去的事 在这个项目中，我们发现了两个主要的电生理变化 大鼠海马神经元增龄：1)突触频率降低 增强(易化)；和2)电压门控钙离子增加 涌入。这些结果和其他结果对总的钙离子有贡献 脑老化与痴呆症假说。在最近一段时间里， 单通道膜片钳结构适用于脑老化研究 并鉴定出有效的L型钙离子膜密度增加 经络作为随年龄变化的潜在分子基础，见 在细胞水平上。 这里，L类钙通道增加是一种特殊的假设。 两种功能受损的关键机制(突触增强或棘波 与衰老哺乳动物神经元的死亡易感性 将会受到考验。研究将在大鼠海马片和 长期培养的L钙通道丰富的海马神经细胞。 重复激活突触对大鼠脑电地形图和波幅的影响 成年和老年大鼠海马片神经元内钙离子瞬变 研究了利用快速紫外光兼容共聚焦激光扫描显微镜 细胞内电生理同时进行的钙离子显像 正在录音。多种特定的通道阻滞剂和激酶调节剂将 用于定义关键的钙离子进入途径。这些研究将确定 突触后钙瞬变，特别是通过L通道是否可以 调节神经元短期突触可塑性并参与改变 在老化的脑神经元中。在细胞培养的平行研究中， 细胞死亡中依赖时间的离子通道变化将被测试，通过 研究细胞对兴奋性毒性易感性的差异 L式经络的不同互补。单通道录制，钙离子 成像、药物阻断和激酶调节将被用来确定 Ca~(2+)是坏死和细胞凋亡的关键来源。

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.