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，受胞质钙的强烈影响。至 调节钙，细胞内有细胞器隔离和 在细胞膜上释放钙和钙转运蛋白，从而排出钙 或者让Ca进入。这笔赠款有三个目标。一是探索 横纹肌内库钙释放的机制 文昌鱼的肌层)和分泌细胞(大鼠 腹膜肥大细胞)。胞质内的钙离子将由荧光素监测 钙指示剂，使用荧光显微镜、显微荧光法和贴片 电压钳位。之所以选择这些制剂是因为它们提供了独特的 提出了实验的有利条件；获得的见解如下 几乎肯定也适用于哺乳动物的肌肉和其他分泌物 细胞。第二个目标是确定调节钙离子的钙通道的特征 进入肌肉，钙通道将在成人和胚胎中进行研究 骨骼肌，以及已插入肌型钙通道的卵母细胞 在先前注射的信使核糖核酸的指导下进入细胞膜。 将特别注意(A)离子选择性的机理， 这对于运输蛋白质具有至关重要的意义，因为它具有 选择性地传输低浓度存在的离子，以及(B) 二氢吡啶类药物与钙通道相互作用的临床研究 被认为是一种特异性的、高亲和力的钙离子标志物的拮抗剂 经络，已成为钙的生化研究的基础 频道。第三个目标是测试钙离子内流(例如，通过 抗原激活的钙通道)有助于胞浆内钙离子的增加 在肥大细胞中。如果找到以流入为中介的组件，将尝试 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.