Tirri R, Vornanen M, Lehto H
Acta Physiol Scand. 1982 Nov;116(3):257-63. doi: 10.1111/j.1748-1716.1982.tb07139.x.
Single spontaneously beating myocardial cells were prepared by mechanical or enzymatical isolation. Using a TV camera and videotape recorder, beating parameters were characterized in different buffer solutions in regard to temperature and integrity of sarcolemma, which was tested by ability of cells to exclude a vital stain, Evans blue. The mechanically disaggregated cells were totally permeable to this stain, but about 60% of the enzymatically isolated myocytes were able to exclude the stain. The myocytes prepared in the presence of calcium were most tolerant to physiological concentration of calcium. Contractions were mainly of phasic type where the velocity of contraction wave was very slow (50-330 microns/s). The velocity was not correlated to the beat rate. Temperature dependence of the velocity was positively correlated with the integrity of sarcolemma. Beat rate was inversely related to the integrity of sarcolemma being slowest in calcium tolerant enzymatically isolated cells. Beat rate of calcium sensitive myocytes was higher but unstable and the temperature dependence of the rate was steeply reduced and even reversed during the incubation. Some calcium tolerant myocytes generated occasionally an electric type of contraction which came in bursts and was characterized by synchronous sarcomere shortening without any contraction wave.
通过机械或酶解分离制备单个自发搏动的心肌细胞。使用电视摄像机和录像机，在不同缓冲溶液中，根据温度和肌膜完整性对搏动参数进行表征，肌膜完整性通过细胞排除活体染料伊文思蓝的能力来测试。机械解离的细胞对这种染料完全通透，但约60%的酶解分离的心肌细胞能够排除该染料。在有钙存在的情况下制备的心肌细胞对生理浓度的钙耐受性最强。收缩主要为相性收缩，收缩波速度非常缓慢（50 - 330微米/秒）。该速度与搏动频率无关。速度的温度依赖性与肌膜完整性呈正相关。搏动频率与肌膜完整性呈负相关，在耐钙的酶解分离细胞中最慢。钙敏感心肌细胞的搏动频率较高但不稳定，且在孵育过程中频率的温度依赖性急剧降低甚至反转。一些耐钙心肌细胞偶尔会产生电类型的收缩，这种收缩呈突发状，其特征是肌节同步缩短而无任何收缩波。
