EXCITATION-CONTRACTION COUPLING IN SKELETAL MUSCLE

化学传播机制的可能性，涉及 肌醇(1，4，5)三磷酸(InsP3)作为第二信使 负责骨骼肌的兴奋-收缩偶联 将在生理/生化实验中进行研究。这个 黄曲霉毒素诱导的肌醇磷酸盐的释放 骨骼肌电活动的研究将通过 黄曲霉代谢成分的生化分析 肌肉迅速冻结。InsP3和其他肌醇的能力 磷酸盐(环状InsP3)快速诱导细胞释放 肌浆网(SR)将使用光学方法进行评估 蒙皮骨骼肌纤维的技术。信号的调制 几个特工的这种能力也将得到调查。小说 快速释放钙离子和肌醇磷酸盐的生产技术 (使用可光释放的衍生物)将被开发，以便 研究SR对可能的激动剂的动力学反应。 这些研究将提供重要的动力学信息 钙离子释放生理过程的化学调控 它们将补充我们关于生物多样性的新发现。 E-C耦合中的传输延迟。钠和钾的作用 T管去极化中的电导和可能的离子 耗尽/积累现象的研究将借助 电位型染料。电压依赖的可能性 磷脂酶C活性内源性存在于T小管 膜将直接在体外进行测试。藤壶的研究 肌肉纤维将使我们能够评估肌醇的作用 磷酸盐对无脊椎动物肌肉和意志E-C偶联的影响 深入了解细胞外钙在细胞外营养中的作用 对这一过程的监管。

The possibility that a chemical transmission mechanism, involving inositol (1,4,5) trisphosphate (InsP3) as a second messenger, is responsible for excitation-contraction coupling in skeletal muscle will be studied in physiological/biochemical experiments. The release of phosphoinositide-derived inositol phosphates induced by the electrical activation of skeletal muscle will be studied by the biochemical analysis of metabolic constituents obtained from rapidly frozen muscles. The ability of InsP3 and other inositol phosphates (cyclic InsP3) to rapidly induce release from the sarcoplasmic reticulum (SR) will be assessed using optical techniques in skinned skeletal muscle fibers. The modulation of this ability by several agents will also be investigated. Novel techniques to produce rapid release of Ca2+ and inositol phosphates (using photoreleasable derivatives) will be developed in order to investigate the kinetic response of the SR to putative agonists. These studies will give important kinetic information on the chemical modulation of the physiological process of Ca2+ release and they will complement our new findings about the nature of the transmission delay in E-C coupling. The role of Na and K conductances in the T-tubule depolarization and in possible ion depletion/accumulation phenomena will be studied with the aid of potentiometric dyes. The possibility that voltage dependent phospholipase C activity is endogenously present in the T tubule membranes will be directly tested in vitro. Studies in barnacle muscle fibers will allow us to evaluate the role of inositol phosphates on the E-C coupling of invertebrate muscle and will provide insights into the role of extracellular Ca in the regulation of this process.