骨骼肌肌浆网钙释放激活的时间进程。
Time course of activation of calcium release from sarcoplasmic reticulum in skeletal muscle.
作者信息
Simon B J, Schneider M F
机构信息
Department of Biological Chemistry, University of Maryland School of Medicine, Baltimore, Maryland 21201.
出版信息
Biophys J. 1988 Dec;54(6):1159-63. doi: 10.1016/S0006-3495(88)83050-9.
Myoplasmic free calcium transients were measured with antipyrylazo III in voltage clamped segments of frog skeletal muscle fibers and were used to calculate the rate of release (Rrel) of calcium from the sarcoplasmic reticulum. Intramembrane charge movement was measured for the same pulses in the same fibers. During a depolarizing pulse Rrel rose to an early peak and then decayed relatively rapidly but incompletely due to calcium-dependent inactivation (Schneider M.F., and B.J. Simon. 1988. J. Physiol. (Lond.). 405:727-745). Two approaches were used to determine release activation independent of the effects of inactivation: (a) a mathematical correction based on the assumption that inactivation was a process occurring in parallel with and independently of activation; (b) an experimental procedure in which release was maximally inactivated by a large short prepulse and then the remaining noninactivatable component of release was monitored during a subsequent test pulse. Both procedures gave the same time course of activation of release. Release activation paralleled the time course of intramembrane charge movement but was delayed by a few milliseconds.
利用安替比拉宗III在蛙骨骼肌纤维的电压钳制节段中测量肌质游离钙瞬变，并用于计算肌浆网钙释放速率（Rrel）。在相同纤维中对相同脉冲测量膜内电荷移动。在去极化脉冲期间，Rrel上升至早期峰值，然后由于钙依赖性失活而相对迅速但不完全地衰减（Schneider M.F.和B.J. Simon. 1988. 《生理学杂志》（伦敦）。405:727 - 745）。采用两种方法来确定与失活效应无关的释放激活：（a）基于失活是与激活并行且独立发生的过程这一假设的数学校正；（b）一种实验程序，其中通过大的短预脉冲使释放最大程度失活，然后在随后的测试脉冲期间监测释放的剩余不可失活成分。两种程序给出了相同的释放激活时间进程。释放激活与膜内电荷移动的时间进程平行，但延迟了几毫秒。
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