Palmer R E, Brady A J, Roos K P
Cardiovascular Research Laboratory, School of Medicine, University of California at Los Angeles 90095, USA.
Am J Physiol. 1996 Feb;270(2 Pt 1):C697-704. doi: 10.1152/ajpcell.1996.270.2.C697.
Single rat left ventricular myocytes were attached at both ends using a newly described double-barreled micropipette technique. This attachment procedure enabled the measurement of the active and passive mechanical properties of chemically skinned cells that showed little structural deformation. The force and oscillatory stiffness (100 Hz) of the cells were measured with a high signal-to-noise ratio, and the sarcomere length throughout the entire cell was monitored using image analysis. The passive properties were investigated from the resting sarcomere length to > 3 microns. Analysis of the sarcomere behavior indicated a high level of homogeneity throughout the cell. The attachment method supported the full activation of the cells by increased free Ca2+ (pCa 4.5), which produced 22.3 mN/mm (mean sarcomere length 2.11 microns). A force/pCa relationship was determined, which, when fitted according to the Hill equation, gave parameters of nH = 2.62 and pCa50 = 5.58. The described techniques allow the accurate study of the mechanical properties of single myocytes with increased fidelity and reliability over the preexisting methods.
使用一种新描述的双管微吸管技术将单个大鼠左心室肌细胞的两端进行固定。这种固定方法能够测量化学去表皮细胞的主动和被动力学特性，这些细胞几乎没有结构变形。以高信噪比测量细胞的力和振荡刚度（100赫兹），并使用图像分析监测整个细胞中的肌节长度。从静息肌节长度到大于3微米对被动特性进行了研究。肌节行为分析表明整个细胞具有高度的同质性。该固定方法通过增加游离Ca2+（pCa 4.5）支持细胞的完全激活，这产生了22.3毫牛顿/毫米（平均肌节长度2.11微米）。确定了力/pCa关系，根据希尔方程拟合时，得到的参数为nH = 2.62和pCa50 = 5.58。与现有方法相比，所描述的技术能够以更高的保真度和可靠性准确研究单个肌细胞的力学特性。
