ELECTRIC STUDIES OF EXCITATION, SECRETION & CONTRACTION

许多细胞的生理活动，包括肌肉，神经元和 几个分泌细胞，强烈影响细胞质Ca。 到 调节Ca，细胞具有细胞内细胞器， 释放钙，钙转运蛋白在细胞膜，挤压钙 或者允许Ca进入。 这笔赠款有三个目的。 一是探索 横纹肌内钙释放的机制 文昌鱼的肌节层）和分泌细胞（大鼠 腹膜肥大细胞）。 细胞质Ca将通过荧光定量分析仪进行监测。 钙指示剂，使用荧光显微镜，显微荧光计和贴片 电压箝位 选择这些制剂是因为它们提供了独特的 提出的实验的有利条件;获得的见解是 几乎肯定也适用于哺乳动物的肌肉和其他分泌 细胞 第二个目的是表征钙通道，其调节钙离子 进入肌肉，钙通道将在成人和胚胎中进行研究 骨骼肌和具有插入的肌肉型Ca通道的卵母细胞中 在先前注射的mRNA的指导下进入它们的细胞膜。 将特别注意（a）离子选择性的机理， 这对于转运蛋白来说至关重要， 选择性地输送以低浓度存在的离子，和（B）所述 钙通道与二氢吡啶类药物的相互作用， 拮抗剂，被认为是一个特定的，高亲和力的标志物钙 通道，并已成为生物化学研究的基本钙 渠道 第三个目的是测试Ca内流（例如，通过 抗原激活的Ca通道）有助于细胞质Ca 在肥大细胞中。 如果发现流入介导的组分， 用来记录抗原激活的钙电流

The physiologic activity of many cells, including muscle, neurons and several secretory cells, is strongly influenced by cytoplasmic Ca. To regulate Ca, cells possess intracellular organelles that sequester and release Ca, and Ca transport proteins in the cell membrane, that extrude Ca or allow Ca to enter. This grant has three aims. The first is to explore the mechanism of Ca release from internal stores of a striated muscle (the myotomal lamellae of the chordate Amphioxus) and a secretory cell (the rat peritoneal mast cell). Cytoplasmic Ca will be monitored by a fluorescent Ca indicator, using fluorescence microscopy, microfluorimetry and patch voltage clamp. The preparations were chosen because they offer uniquely favorable conditions for the experiments proposed; the insights gained are almost certain to apply also to mammalian muscle and other secretory cells. The second aim is to characterize Ca channels, which regulate Ca entry into muscle, Ca channels will be studied in adult and embryonic skeletal muscle, and in oocytes that have inserted muscle-type Ca channels into their cell membranes under direction of previously injected mRNA. Special attention will be given to (a) the mechanism of ion selectivity, which is of crucial significance for a transport protein with the task of selectively transporting an ion present at low concentration, and (b) the interaction of Ca channels with dihydropyridines, a clinically used Ca antagonist that is regarded as a specific, high-affinity marker for Ca channels and has become fundamental for biochemical studies of Ca channels. A third aim is to test whether Ca-influx (e.g. through an antigen-activated Ca channel) contributes to the increase in cytoplasmic Ca in mast cells. If an influx-mediated component is found, attempts will be made to record antigen-activated Ca currents.