EXCITATION-CONTRACTION COUPLING IN SKELETAL MUSCLE

目前认为，细胞内钙释放的机制可能与细胞内钙离子释放有关。 肌浆网(SR)在骨骼肌中运行，受 横管系统的膜电位。借助于…… 电生理和光学技术，建议研究 细胞内钙离子浓度在两个水平上的调节：a) 肌浆网启动肌浆网改变的机制 [Ca~(2+)]在释放过程中的激活和b)机制 将局部的钙释放SR传播到其余部位 肌浆。这些实验的目的是获得关于关键技术的准确信息 关于这些流程可以提出的问题：SR是否发布了 Ca~(2+)是通过大渗透性还是小渗透性？该组织的作用是什么？ 钙-诱导-钙释放过程？是钙离子释放的过程 位于青蛙骨骼肌纤维的Z线上？我在那里陡峭 肌节内(Ca2+i梯度)，通过扩散迅速消散 钙离子进入肌原纤维间隙？其中几个问题的答案 几十年来一直在该领域悬而未决。尽管如此，技术 快速闪光光解、钙离子检测和成像技术的研究进展 让它们现在有可能得到实验性的回答。结果是 可能会导致以我们所理解的方式发展一幅新的图景 今天的肌肉生理学。可想而知，肌肉的治疗方法 由于缺乏准确的定义而尚未被很好地理解的疾病 在涉及细胞内钙调节的问题中，可能是 鉴于这些结果，我们达成了一致意见。最后，由于此应用程序处理 对于细胞内钙调节的一般性问题， 结论不仅适用于骨骼肌、心肌和平滑肌， 但几乎对任何细胞都是如此，因为胞内钙离子介导了多种不同的 生物学中的细胞过程。

It is currently believed that the mechanism of Ca2+ release from the sarcoplasmic reticulum (SR) operates, in skeletal muscle, under control of the membrane potential of the transverse tubular system. With the aid of electrophysiological and optical techniques, it is proposed to investigate the regulation of the intracellular Ca2+ concentration at two levels: a) the mechanisms by which the SR may initiate the changes in myoplasmic [Ca2+] during the activation of the release process and b) the mechanisms of propagation of the localized Ca2+ release SR to the rest of the myoplasm. The experiments aim to obtain precise information about critical questions that can be raised about these processes: Does the SR releases Ca2+ by means of a large or a small permeability? What is the role of the calcium-induce-calcium release process? Is the Ca2+ release process localized at the Z lines in frog skeletal muscle fibers? Me there steep intra-sarcomeric (ca2+i gradients that dissipate rapidly by diffusion of Ca2+ to the myofibrillar space? The answers to several of these questions have been pending in the field since decades. Nevertheless, technological advances in fast flash photolysis, Ca2+ detection, and imaging techniques make it possible for them to be answered experimentally now. The results may lead to the development of a new picture in the way that we understand muscle physiology today. It is conceivable that the cure for muscle diseases not well understood yet due to the lack of an accurate definition of the problems involved in the regulation of intracellular Ca2+, may be reached in view of these results. Finally, since this application deals with general questions about intracellular Ca2+ regulation, the conclusions will not only apply to skeletal, cardiac, and smooth muscle, but to almost any cell, since cytosolic Ca2+ mediates a large variety of cellular processes in biology.