Isenberg G, Beresewicz A, Mascher D, Valenzuela F
Basic Res Cardiol. 1985;80 Suppl 1:117-21. doi: 10.1007/978-3-662-11041-6_23.
In isolated myocytes from mammalian ventricles a fast and a slow component in the contractile response to depolarizing voltage clamp steps were identified. The potential dependence of the slow component was identical to the activation curve of iCa. The fast component, however, remained at its maximal amplitude at potentials positive to +10 mV (up to +100 mV), in which potential range iCa declined and eventually disappeared. The results suggest that the slow component may be activated by Ca++ entering through sarcolemmal Ca channels, whereas the fast component depends on Ca release from intracellular sites and may depend on both Cai and voltage.
在从哺乳动物心室分离出的单个心肌细胞中，对去极化电压钳位步骤的收缩反应被识别出有一个快速成分和一个缓慢成分。缓慢成分的电位依赖性与内向钙电流（iCa）的激活曲线相同。然而，快速成分在正于+10 mV（直至+100 mV）的电位下保持其最大幅度，在此电位范围内iCa下降并最终消失。结果表明，缓慢成分可能由通过肌膜钙通道进入的Ca++激活，而快速成分则依赖于细胞内位点的钙释放，并且可能同时依赖于细胞内钙（Cai）和电压。
