CALCIUM WAVES AND ARRHYTHMIAS

描述（改编自申请人的摘要）：长期 这项建议的目的是增加我们对 Ca 2+波的关系，改变细胞内Ca 2+循环， 心律失常的机制。 申请人建议， 钙波的细胞和亚细胞机制的识别是 这对于理解正常和异常的初始事件至关重要， 不正常的节奏 细胞内Ca 2+稳态将在三个 水平包括：1）从内皮下分离的单个浦肯野细胞 正常和致心律失常性梗死犬心脏; 2）聚集物或 从正常和致瘤性分离的浦肯野细胞的“链” 梗塞的犬心脏;和3）从右侧分离的工作小梁 正常和致心律失常性梗死大鼠心脏的心室。 具体目标 1将测试的假设，浦肯野细胞存活后， 心肌梗死患者的钙循环异常， 钙循环导致异常（即，电的 活动 这将涉及全细胞Ca 2+瞬变的测量 （fura-2荧光）和全细胞Ca 2+电流通过标准全细胞 电压箝位技术。 具体目标2检验了Ca 2 + 振荡是重要的调节信号， 以及细胞之间。 浦肯野细胞的聚集体将用 穿孔贴片技术和细胞内Ca 2+将被可视化为 Fluo-3荧光。 具体目标3检验了以下假设： 触发的传播性收缩（TPC）的起始和传播是 由于异常的电活动和传播的Ca 2+波， 肌膜通过缓冲Ca 2+的能力调节钙的增殖， 去极化诱导Ca 2+释放。 一种多细胞制剂（即， 工作小梁）将用于研究Ca 2+波， Fluo-3荧光。

DESCRIPTION (adapted from the applicant's abstract): The long-term objective of this proposal is to increase our understanding of the relationship of Ca2+ waves, altered intracellular Ca2+ cycling in the mechanisms of cardiac arrhythmias. The applicant proposes that the identification of the cellular and subcellular mechanisms of Ca2+ waves is crucial for the understanding of the initiating events of both normal and abnormal rhythms. Intracellular Ca2+ homeostasis will be studied on three levels including: 1) single Purkinje cells isolated from the subendocardium of normal and arrhythmogenic infarcted canine hearts; 2) aggregates or "strands" of Purkinje cells isolated from normal and arrhythmogenic infarcted canine hearts; and 3) working trabeculae isolated from the right ventricles of normal and arrhythmogenic infarcted rat hearts. Specific aim 1 will test the hypotheses that Purkinje cells that survive after a myocardial infarction have abnormal Ca2+ cycling and that this altered calcium cycling contributes to abnormal (i.e., arrhythmogenic) electrical activity. This will involve the measurement of whole-cell Ca2+ transients (fura-2 fluorescence) and whole-cell Ca2+ currents via standard whole-cell voltage clamp techniques. Specific aim 2 tests the hypothesis that Ca2+ oscillations are important regulatory signals both within a single cell as well as between cells. Aggregates of Purkinje cells will be studied with the perforated patch technique and intracellular Ca2+ will be visualized as fluo-3 fluorescence. Specific aim 3 tests the hypotheses that the initiation and propagation of triggered propagated contraction (TPCs) are due to abnormal electrical activity and propagating Ca2+ waves, and that the sarcolemma modulates calcium propagation by its ability to buffer Ca2+ and depolarization induced Ca2+ release. A multicellular preparation (i.e., working trabeculae) will be used to study Ca2+ waves that are visualized as fluo-3 fluorescence.