Relaxation of isolated ventricular cardiomyocytes by a voltage-dependent process.
Relaxation of isolated ventricular cardiomyocytes by a voltage-dependent process.
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通过电压依赖性过程松弛离体心室心肌细胞。
DOI：
10.1126/science.3406740
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Ershler,PR
中科院分区：
文献类型：
--
作者：
Bridge,JH;Spitzer,KW;Ershler,PR
在电压钳位的豚鼠心肌细胞上测量细胞的收缩和舒张，以研究肌膜Na+-Ca 2+交换对机械舒张的贡献。细胞从-80到0毫伏夹持显示初始相位和随后的强直性收缩;咖啡因减少或消除相位和扩大强直性收缩。紧张性收缩的松弛率是急剧的电压依赖性，并显着放缓的情况下，肌膜Na+梯度。紧张性收缩引起的Na+梯度的情况下，立即放松时，外部Na+施加，反映激活Na+-Ca 2+交换。看来，电压依赖性Na+-Ca 2+交换可以快速机械地放松哺乳动物的心肌。
Cell contraction and relaxation were measured in single voltage-clamped guinea pig cardiomyocytes to investigate the contribution of sarcolemmal Na+-Ca2+exchange to mechanical relaxation. Cells clamped from -80 to 0 millivolts displayed initial phasic and subsequent tonic contractions; caffeine reduced or abolished the phasic and enlarged the tonic contraction. The rate of relaxation from tonic contractions was steeply voltage-dependent and was significantly slowed in the absence of a sarcolemmal Na+gradient. Tonic contractions elicited in the absence of a Na+gradient promptly relaxed when external Na+was applied, reflecting activation of Na+-Ca2+exchange. It appears that a voltage-dependent Na+-Ca2+exchange can rapidly mechanically relax mammalian heart muscle.