Nifedipine block of capacitative calcium entry in cultured human uterine smooth-muscle cells.
Nifedipine block of capacitative calcium entry in cultured human uterine smooth-muscle cells.
复制标题
硝苯地平阻断培养的人子宫平滑肌细胞中的电容性钙进入。
DOI：
10.1016/s1071-5576(01)00109-5
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Zhang,P
中科院分区：
文献类型：
--
作者：
Young,RC;Schumann,R;Zhang,P
目的确定是否硝苯地平抑制容量钙进入临床相关浓度培养的人肌细胞作为一个模型为human myometrium.MethodsMyocyte文化开始从子宫肌层的足月孕妇进行剖宫产。选择成对细胞进行研究。感兴趣的细胞被来自相邻细胞的细胞间钙波刺激。以这种方式，肌浆网（SR）钙的释放完成与质膜和质膜下空间（SPS）的细胞研究的最小干扰。钙波消耗SR钙储存激活了电容性钙电流，增加了SPS中的钙，并激活了钙激活钾通道。一个细胞贴附patc钳被用来监测外向电流所产生的钙激活这些钾通道。钙绿色-1荧光用于同时监测深层胞质钙浓度的变化。结果硝苯地平以剂量依赖性方式抑制外向钾电流。硝苯地平在100 nmol/L导致大于50%的外向电流减少，表明在该浓度下的电容性钙离子内流的显着抑制。较高浓度的硝苯地平消除外向电流。实验旨在检测硝苯地平对容量性钙离子进入的间接影响是negative.ConclusionNifedipine块的容量性钙离子进入发生在类似的浓度所需的阻断L-型电压激活的钙通道。这些数据表明，当硝苯地平临床用于早产安胎时，阻断容量性钙内流可能是一个重要的作用机制。
ObjectiveTo determine whether nifedipine inhibits capacitative calcium entry at clinically relevant concentrations using cultured human myocytes as a model for human myometrium.MethodsMyocyte cultures were initiated from the myometrium of term pregnant women who underwent cesarean delivery. Paired cells were chosen for study. The cell of interest was stimulated by an intercellular calcium wave from the adjacent cell. In this fashion, release of sarcoplasmic reticulum (SR) calcium was accomplished with minimal disturbance of the plasma membrane and the subplasmalemmal space (SPS) of the cell studied. Depletion of the SR calcium stores by the calcium wave activated the capacitative calcium current, elevated calcium in the SPS, and activated calcium-activated potassium channels. A cell-attached patc clamp was used to monitor the outward current resulting from the calcium activation of these potassium channels. Calcium green-1 fluorescence was used to simultaneously monitor changes of the deep cytosolic calcium concentrations. Experiments were performed at varying concentrations of nifedipine (0–10 μmol/L).ResultsNifedipine reduced outward potassium currents in a dose-dependent manner. Nifedipine at 100 nmol/L resulted in greater than a 50% reduction of outward current, indicating a significant inhibition of capacitative calcium entry at that concentration. Higher concentrations of nifedipine abolished outward current. Experiments designed to detect indirect effects of nifedipine on capacitative calcium entry were negative.ConclusionNifedipine block of capacitative calcium entry occurred at concentrations similar to those required to block L-type voltage-activated calcium channels. These data suggest that block of capacitative calcium entry may be an important mechanism of action when nifedipine is clinically used for tocolysis of preterm labor.