Sarcomere motion in isolated cardiac cells.
Sarcomere motion in isolated cardiac cells.
复制标题
分离的心肌细胞中的肌节运动。
作者：
G. Rieser;R. Sabbadini;P. Paolini;M. Fry;G. Inesi
计算机图像分析技术已被用来研究离体哺乳动物心肌细胞的肌节动力学。通过用透明质酸酶-胶原酶溶液灌注成年兔心脏制备细胞;它们在10（-6）M Ca 2+存在下表现出阶段性收缩。通过相位显微镜和连接在小型计算机中的摄像机来观察解离的细胞。通过利用信号平均和对比度增强的算法处理数字化细胞图像，以产生显示个体肌节位置和缩短与时间的数据，使得可以在自发收缩的细胞中观察到肌节激活的模式。与全细胞缩短和横纹位移的记录相比，计算机图像分析提供了一个更可靠的指示肌节缩短的时间过程和顺序。自发性收缩细胞表现出连续的肌节缩短，从一端开始，以恒定的速度纵向传播，通常在100- 150 μ m/s，搏动率为40 min-1。初始肌节缩短的速度似乎随着Ca 2+的升高而增加。这些观察结果与钙诱导的钙释放的再生机制一致。
Computerized image-analysis techniques have been employed to examine the sarcomere dynamics of isolated mammalian cardiac myocytes. The cells were prepared by perfusion of adult rabbit hearts with hyaluronidase-collagenase solutions; they exhibited phasic contractions in the presence of 10(-6) M Ca2+. The dissociated cells were visualized by phase microscopy and a video camera interfaced in a minicomputer. Digitized cell images were processed by an algorithm utilizing signal averaging and contrast enhancement to yield data showing individual sarcomere position and shortening vs. time, so that patterns of sarcomere activation could be observed in spontaneously contracting cells. Compared to records of whole-cell shortening and of striation displacement, computerized image analysis provided a much more faithful indication of time course and sequence of sarcomere shortening. Spontaneously contracting cells showed sequential sarcomere shortening beginning at one end and propagating longitudinally with a constant velocity, typically at 100--150 micron/s for beat rates of 40 min-1. Velocities of initial sarcomere shortening appeared to increase with elevated Ca2+. These observations are consistent with a regenerative mechanism of calcium-induced calcium release.