CALCIUM WAVES AND ARRHYTHMIAS

描述(改编自申请人的摘要)：长期 这项建议的目的是加深我们对 钙波与心肌细胞内钙循环的关系 心律失常的机制。申请人建议 钙波的细胞和亚细胞机制的鉴定 对于理解正常的和非正常的 不正常的节奏。将从三个方面研究细胞内钙离子的动态平衡 水平包括：1)从心内膜下分离的单个浦肯野细胞 正常和致心律失常的梗死犬心脏；2)聚集体或 从正常和致心律失常患者体内分离的浦肯野细胞“链” 梗死犬心脏；3)从右侧分离的工作小梁 正常和致心律失常性心肌梗死大鼠的心室。特定目标 1将检验这样的假设，即浦肯野细胞在 心肌梗死有异常的钙循环，这种改变 钙循环有助于异常(即，致心律失常)电 活动。这将涉及全细胞钙瞬变的测量。 (Fura-2荧光)和通过标准全细胞的全细胞钙电流 电压钳位技术。《特定目标2》验证了钙离子的假设 振荡是一种重要的调节信号，在单个细胞内 细胞之间也是如此。浦肯野细胞聚集体的研究将用 穿孔补片技术和细胞内钙离子将被可视化为 Fluo-3荧光。《特定目标3》测试了以下假设 触发传播收缩(TPC)的启动和传播 由于异常的电活动和传播的钙波，以及 肌膜通过缓冲钙离子和钙离子的能力调节钙离子的传播 去极化可引起钙离子释放。多细胞制剂(即， 工作小梁)将被用来研究被可视化为 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.