MYOCARDIAL SARCOMERE MECHANICS

这项研究的目的是揭示某些潜在的机制， 心脏力学的基本特征。 为此，我们将执行 在三个层次的每一个平行实验， 组织：孤立的小梁，孤立的单个肌原纤维，和 分离的肌丝。 第一个涉及一种用于这种 实验室一段时间。 离体心脏肌节力学 可以以高空间和时间分辨率研究骨小梁。 第二种是单离体肌原纤维，是最近制备的 开发 它的优点是，制备中的每一个肌节 由于肌节是串联的， 由任何给定的肌节产生的是在肌节末端测量的， 试样 因此，可以建立每个肌节的力学 毫不含糊 第三种制备是体外运动性测定， 荧光标记的肌动蛋白丝的运动可以 在基质上种植的肌球蛋白头的草坪上观察。 通过 结合速度和张力的测量， 可以被建立。 通过同时使用这三种制剂 实验，将有可能剖析基本的机制， 力学的特点。 我们计划研究长度-张力关系， 失活、张力增强、拉伸效应以及其他相关的 机械现象 通过观察一种现象是否出现 在一定的结构组织水平上， 迅速排除某些假定的机制。 我们可以更加关注 强烈地对别人。 探索机械现象的能力 同一实验室的三级组织应允许快速 进一步了解心脏收缩的基本原理。

The aim of this research is to uncover the mechanisms underlying certain basic features of cardiac mechanics. To do so, we will carry out parallel experiments at each of three hierarchical levels of organization: isolated trabeculae, isolated single myofibrils, and isolated myofilaments. The first involves a preparation used in this laboratory for some time. Sarcomere mechanics of isolated cardiac trabeculae can be investigated with high spatial and temporal resolution. The second, single isolated myofibrils, is a preparation recently developed. It has the advantage that every sarcomere in the preparation can be observed, and since sarcomeres are in series, the tension generated by any given sarcomere is that measured at the end of the specimen. Thus, the mechanics of each sarcomere can be established unambiguously. The third preparation is the in vitro motility assay, in which the motion of fluorescently labelled actin filaments can be observed over a lawn of myosin heads planted on a substrate. By combining measurements of velocity and tension, mechanics of filaments can be established. By using these three preparations in parallel experiments, it will be possible to dissect mechanisms underlying basic features of mechanics. We plan to study length-tension relations, deactivation, tension-enhancement, effect of stretch, and other pertinent mechanical phenomena. By observing whether or not a phenomenon shows up at a certain level of structural organization, it will be possible to swiftly rule out certain putative mechanisms. We may then focus more intensely on others. The ability to explore mechanical phenomena at three levels of organization in the same laboratory should permit rapid advance in understanding of the basic principles of cardiac contraction.