Cytosolic calcium staircase in cultured myocardial cells.
Cytosolic calcium staircase in cultured myocardial cells.
复制标题
培养心肌细胞中的胞质钙阶梯。
DOI：
10.1161/01.res.61.6.934
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发表时间：
1987
影响因子：
20.1
通讯作者：
Clusin,WT
中科院分区：
文献类型：
--
作者：
Lee,HC;Clusin,WT
为了阐明张力阶梯的机制，我们在鸡胚心肌细胞聚集体中加载了荧光胞质钙指示剂indo 1。将indo - 1荧光的波动与细胞自发跳动和细胞内电流脉冲刺激时的细胞边缘运动记录进行比较。负载Indo - 1的聚集体在每个跨膜动作电位期间表现出荧光瞬态。瞬态的上升阶段是快速的，但衰减阶段是缓慢的（几百毫秒），并且在时间过程上与细胞边缘运动的光学记录中所见的舒张期相似。短暂的去极化电流脉冲加速心跳频率，在边缘运动和收缩期[Ca2+]i中产生上升阶梯。舒张期[Ca2+]i也有类似的阶梯，这也通过舒张期细胞边缘运动反映出来。舒张[Ca2+]i阶梯的存在可能为心脏力-频率关系的机制提供新的见解。
To elucidate the mechanism of the tension staircase, chick embryonic myocardial cell aggregates were loaded with the fluorescent cytosolic calcium indicator, indo 1. Fluctuations in indo 1 fluorescence were compared with recordings of cell edge movement during spontaneous beating and during stimulation by intracellular current pulses. Indo 1-loaded aggregates exhibit fluorescence transients during each transmembrane action potential. The rising phase of the transients is rapid, but the decaying phase is slow (several hundred msec) and is similar in time course to the pandiastolic relaxation seen in the optical recordings of cell edge movement. Acceleration of beat frequency by brief depolarizing current pulses produces an ascending staircase in both edge movement and systolic [Ca2+]i. There is a similar staircase in the diastolic [Ca2+]i, which is also reflected by diastolic cell edge movement. The existence of a diastolic [Ca2+]i staircase may provide new insight into the mechanism of the force-frequency relation in the heart.