Whole-cell and single-channel calcium currents of isolated smooth muscle cells from saphenous vein.
Whole-cell and single-channel calcium currents of isolated smooth muscle cells from saphenous vein.
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来自隐静脉的分离平滑肌细胞的全细胞和单通道钙电流。
DOI：
10.1161/01.res.60.4.523
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发表时间：
1987
影响因子：
20.1
通讯作者：
Brown,AM
中科院分区：
文献类型：
--
作者：
Yatani,A;Seidel,CL;Allen,J;Brown,AM
用膜片钳技术记录酶法分离的狗隐静脉细胞全细胞和单通道钙电流。从-90 mV至-40 mV的保持电位到负电位的测试脉冲引发了快速失活且以电压依赖性方式（称为I低，表示低阈值）的电流。第二个钙电流即使在相对正的保持电位（-30至-10 mV）下也持续存在，需要更强的去极化才能获得最大电流，并且缓慢失活（I高表示高阈值）。我高运输钡比钙多，而我低运输两种离子相等。单通道电流记录（90 mM钡）显示了较大的电导，激活在相对正的电位和较小的（约三分之一）电导，激活在弱去极化。尼群地平抑制I高，其作用是电压依赖性的，如在心肌细胞中所观察到的，尽管在静脉细胞中静息通道的阻断更大（KR约为10（-8）M）。立体异构体（-）Bay K 8644的暴露量在高水平时增加，但在低水平时没有增加。（-）Bay K 8644还增加通道活性，延长大电导电流的开放时间。因此，两种类型的钙通道，不同的电位依赖性的激活和失活，钙/钡的选择性，单通道电导，和敏感性，二氢吡啶被确定在平滑肌细胞分离的大皮肤静脉。
Whole-cell and single-channel calcium currents in enzymatically isolated dog saphenous vein cells were recorded by the patch-clamp method. Test pulses to negative potentials from holding potentials of -90 to -40 mV elicited currents that inactivated quickly and in a voltage-dependent manner (called I low for low threshold). A second calcium current persisted even at relatively positive holding potentials of -30 to -10 mV, required stronger depolarizations for maximum current, and inactivated slowly (I high for high threshold). I high transported barium more than calcium, whereas I low transported the two ions equally. Single-channel current records (90 mM barium) showed a larger conductance that activated at relatively positive potentials and a smaller (about one-third) conductance that activated at weak depolarizations. Nitrendipine suppressed I high, and the effect was voltage dependent as observed in cardiac cells, although block of resting channels was much greater in vein cells (KR approximately 10(-8) M). Exposure to the stereoisomer (-)Bay K 8644 increased I high but not I low. The (-)Bay K 8644 also increased the channel activity and prolonged the open time of the larger conductance current. Thus, two types of calcium channels, differing in potential-dependence of activation and inactivation, calcium/barium selectivity, single-channel conductance, and sensitivities to dihydropyridines were identified in smooth muscle cells isolated from a large cutaneous vein.