DEVELOPMENT OF CARDIAC EXCITATION/CONTRACTION COUPLING

尽管最近对Ca2+的一般理解取得了许多进展， 在心脏兴奋-收缩（EC）偶联过程中， 已知关于各种分子的功能组装 胚胎发育过程中EC偶联的组分 发展 考虑到许多药物 用于治疗心脏病的药物以某种方式影响Ca2+处理 在怀孕的母亲中，这些可能会影响胎儿， 不同.第二，这可能是正常的发展， 先天性心脏病的发病机制发生了改变。 在这一提议中， 这些实验旨在测试心脏的功能方面 EC偶联与心脏连接复合体平行发展， 胚胎心脏中特异蛋白的表达。 交界性 复合物是EC偶联的结构表现， 最近详细报道了鸡胚中的电子和 共聚焦显微镜 据估计， EC偶联的发展将平行于外观和表达 关键的蛋白质成分。 将采用的方法包括 膜片钳，钙瞬变测量，荧光共聚焦 显微镜和Western印迹。 这些研究将在 鸡胚是胚胎学研究最多的模型， 包括EC偶联的大多数细胞系统的发展。 平行 实验将在发育中的小鼠心脏中进行， 与哺乳动物物种进行比较。 具体目标是：（1） 确定钙诱导的钙释放的正常发展， 肌浆网; 2）确定正常发育的 从细胞质中去除Ca2+的机制;和3）确定 心脏EC中关键蛋白的相对表达和组装 偶合器. 这项工作的长期目标是了解 发展调节细胞内Ca 2+的关键机制， 从最早的心管到成熟的四个心脏 有腔的心脏

Despite many recent advances in the general understanding of Ca2+ handling during cardiac excitation-contraction (EC) coupling, little is known regarding the functional assembly of the various molecular components of EC coupling during the course of embryological development. This is critical information considering that many drugs used in the treatment of heart disease affect Ca2+ handling in some way and, in the pregnant mother, these are likely to affect the fetus differently. Secondly, it is likely that the normal development of these mechanisms is altered in congenital heart disease. In this proposal, the experiments are designed to test how functional aspects of cardiac EC coupling develop in parallel with cardiac junctional complexes and expression of specific proteins in embryonic heart. Junctional complexes are the structural manifestations of EC coupling which have recently been reported in detail in the chick embryo with electron and confocal microscopy. It is anticipated that the time course of development of EC coupling will parallel the appearance and expression of the key protein components. The approaches that will be used include patch clamping, measurements of Ca2+ transients, fluorescence confocal microscopy, and Western blotting. These studies will be carried out in the chick embryo which is the most studied model for embryological development of most cellular systems including EC coupling. Parallel experiments will be conducted in the developing mouse heart for comparison with a mammalian species. The Specific Aims are: 1) to determine the normal development of Ca-induced-Ca-release from the sarcoplasmic reticulum; 2) to determine the normal development of the mechanisms which remove Ca2+ from the cytoplasm; and 3) to determine the relative expression and assembly of the key proteins in cardiac EC coupling. The long term objective of this work is to understand the development of the critical mechanisms which regulate cytosolic Ca2+ on a beat-to-beat basis from the earliest heart tube to the mature four- chambered heart.