Tarr M, Trank J W, Leiffer P, Shepherd N
Circ Res. 1981 Feb;48(2):200-6. doi: 10.1161/01.res.48.2.200.
Recent experiments using laser diffraction techniques to determine the time course and extent of sarcomere shortening in thin bundles of cardial tissue have given results which suggest that the velocity of sarcomere shortening in cardiac muscle is independent of the developed force (Nassar et al., 1974; Krueger and Pollack, 1975). However, the anatomical complexity of the intact tissue precludes a definite interpretation of the data, since the exact relationship between the force being borne by the total tissue to the force being borne by any observed group of sarcomeres is uncertain. The single frog atrial cell provides a simple cardiac preparation in which the relationship between sarcomere velocity and sarcomere force is well defined, since these cells are only 1-2 myofibrils wide. The purpose of the present investigation was to determine if sarcomere velocity in the single frog atrial cell is dependent on force by measuring the time course of sarcomere shortening in single cells under conditions in which the cell developed markedly different forces. The results presented in this paper give direct evidence that the velocity of sarcomere shortening in the single cardiac cell depends on the force being developed by the sarcomeres. Thus, cardiac sarcomeres have a type of force-velocity relationship, although the exact nature of this relationship could not be determined in these experiments.
最近利用激光衍射技术来确定心肌薄束中肌节缩短的时间进程和程度的实验给出了一些结果，这些结果表明心肌中肌节缩短的速度与所产生的力无关（纳萨尔等人，1974年；克鲁格和波拉克，1975年）。然而，完整组织的解剖复杂性使得对数据的明确解释变得不可能，因为整个组织所承受的力与任何观察到的一组肌节所承受的力之间的确切关系尚不确定。单个青蛙心房细胞提供了一种简单的心脏标本，其中肌节速度与肌节力之间的关系是明确的，因为这些细胞只有1 - 2个肌原纤维宽。本研究的目的是通过测量单个细胞在产生明显不同力的条件下肌节缩短的时间进程，来确定单个青蛙心房细胞中的肌节速度是否取决于力。本文给出的结果直接证明了单个心脏细胞中肌节缩短的速度取决于肌节所产生的力。因此，心肌肌节具有一种力 - 速度关系，尽管在这些实验中无法确定这种关系的确切性质。
