Díaz M E, Trafford A W, O'Neill S C, Eisner D A
Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool L69 3BX, UK.
Pflugers Arch. 1997 Nov;434(6):852-4. doi: 10.1007/s004240050475.
The Ca content of the sarcoplasmic reticulum (s.r.) was measured in voltage-clamped rat ventricular myocytes from the integral of the Na-Ca exchange current evoked by applying caffeine to release the s. r. Ca content. Following spontaneous release of Ca from the s.r., the s.r. Ca content was decreased. The magnitude of this decrease was equal to that of the amount of calcium directly measured to have been pumped out of the cell during the spontaneous release. Following a spontaneous release, the s.r. Ca content recovered linearly. These results are shown to be consistent with the hypothesis that the frequency of spontaneous release is determined by the time taken for the cell and s.r. to reaccumulate the Ca2+ ions pumped out of the cell during spontaneous release.
通过施加咖啡因释放肌浆网（s.r.）钙含量所诱发的钠钙交换电流积分，来测量电压钳制的大鼠心室肌细胞中肌浆网的钙含量。在肌浆网自发释放钙后，肌浆网钙含量降低。这种降低的幅度与在自发释放期间直接测量到的从细胞中泵出的钙量相等。一次自发释放后，肌浆网钙含量呈线性恢复。这些结果表明与以下假设一致，即自发释放的频率由细胞和肌浆网重新积累在自发释放期间从细胞中泵出的Ca2+离子所需的时间决定。
