Satoh H, Sperelakis N
Department of Physiology and Biophysics, University of Cincinnati, College of Medicine, OH 45267.
Eur J Pharmacol. 1993 Feb 16;231(3):443-9. doi: 10.1016/0014-2999(93)90122-x.
The effects of taurine on L-type and T-type Ca2+ channels is isolated 3-day-old embryonic chick heart cells were examined at different intracellular Ca2+ concentrations ([Ca]i), using whole-cell voltage clamp techniques. Experiments were performed at room temperature (22 degrees C) and at a holding potential of -40 mV. When [Ca]i was pCa 7, addition of taurine to the bath solution reduced the L-type Ca2+ current (ICa(L)) at 0 mV by 56.3 +/- 2.8% (n = 5, P < 0.01) at 10 mM, and by 73.2 +/- 2.6% (n = 5, P < 0.001) at 20 mM. At pCa 10, ICa(L) was unaffected (7.2 +/- 3.1%, n = 5, P > 0.05) by 10 mM taurine and was enhanced by 47.3 +/- 2.4% (n = 5, P < 0.01) by 20 mM taurine. Control fast and slow time constants of inactivation at pCa 7 (at +10 mV) were 5.8 +/- 2.8 ms and 28.8 +/- 1.8 ms (n = 4), respectively; neither constant was modified by taurine. At pCa 10, the control fast and slow time constants were 15.8 +/- 1.0 and 67.7 +/- 3.8 ms (n = 4); the fast time constant was not affected by 10-20 mM taurine but the slow time constant was slowed by 14.5 +/- 2.9% (n = 4, P < 0.05) by 10 mM taurine and by 66.2 +/- 2.8% (n = 4, P < 0.001) by 20 mM taurine. The inactivation curve for ICa(L) was not modified by taurine.(ABSTRACT TRUNCATED AT 250 WORDS)
利用全细胞膜片钳技术，在不同的细胞内钙离子浓度（[Ca]i）下，研究了牛磺酸对分离的3日龄鸡胚心脏细胞中L型和T型钙通道的影响。实验在室温（22℃）和-40 mV的钳制电位下进行。当[Ca]i为pCa 7时，在浴液中添加牛磺酸，在10 mM时，0 mV处的L型钙电流（ICa(L)）降低了56.3±2.8%（n = 5，P < 0.01），在20 mM时降低了73.2±2.6%（n = 5，P < 0.001）。在pCa 10时，10 mM牛磺酸对ICa(L)无影响（7.2±3.1%，n = 5，P > 0.05），而20 mM牛磺酸使其增强了47.3±2.4%（n = 5，P < 0.01）。在pCa 7（+10 mV）时，对照的快速和慢速失活时间常数分别为5.8±2.8 ms和28.8±1.8 ms（n = 4）；两者均未被牛磺酸改变。在pCa 10时，对照的快速和慢速时间常数分别为15.8±1.0和67.7±3.8 ms（n = 4）；快速时间常数不受10 - 20 mM牛磺酸影响，但慢速时间常数在10 mM牛磺酸作用下减慢了14.5±2.9%（n = 4，P < 0.05），在20 mM牛磺酸作用下减慢了66.2±2.8%（n = 4，P < 0.001）。ICa(L)的失活曲线未被牛磺酸改变。（摘要截断于250字）
