Isometric contractile properties of single isolated smooth muscle cells
Isometric contractile properties of single isolated smooth muscle cells
复制标题
单个分离的平滑肌细胞的等长收缩特性
作者：
F. Fay
使用多细胞条带研究平滑肌细胞的收缩特性是基于这样的假设，即单个细胞的特性直接反映在整个组织的行为中。然而，完整条带中细胞群体收缩状态的异质性，以及细胞和细胞外纤维成分之间复杂的相互连接，都必须影响测量的机械性能。从蟾蜍胃中分离出可存活的单个平滑肌纤维的方法现在使直接测量单细胞中的力成为可能。我在这里报告了一种等轴测单个分离的平滑肌细胞收缩力量的技术。该方法被用来研究单个平滑肌细胞的力发展的动力学和大小。结果表明，单个细胞每平方厘米的最大作用力与整个组织的最大作用力相当。刺激后主动力量发展的开始是异常缓慢的。对这种延迟的分析表明，它存在于Step(S)中，可能是平滑肌所特有的，由此Ca~(2+)激活收缩机械。
THE use of multicellular strips to study contractile properties of smooth muscle cells rests on the assumption that properties of individual cells are directly reflected in the behaviour of whole tissues. Both the heterogeneity of the contractile state of the cell population in the intact strip, and the complex interconnections between cells and extracellular fibrous elements, however, must influence measured mechanical properties. Methods for isolating viable single smooth muscle fibres from the stomach of the toad, Bufo marinus1,2 now make it possible to make direct measurements of force generation in single cells. I report here a technique for isometrically measuring the force of contraction of a single isolated smooth muscle cell. The method was used to investigate the kinetics and magnitude of force development in a single smooth muscle cell. The results reveal that the maximum force per cm2 of a single cell is comparable with that of whole tissue. The onset of active force development after stimulation is exceptionally slow. Analysis of this delay suggests that it resides in step(s), perhaps unique to smooth muscle, whereby Ca2+ activates the contractile machinery.