IONIC CURRENTS IN SINGLE CELLS FROM HUMAN CYSTIC ARTERY
IONIC CURRENTS IN SINGLE CELLS FROM HUMAN CYSTIC ARTERY
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DOI：
10.1161/01.res.70.3.536
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发表时间：
1992-03-01
影响因子：
20.1
通讯作者：
GILES, WR
中科院分区：
文献类型：
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作者：
AKBARALI, HI;WYSE, DG;GILES, WR
应用膜片钳技术研究人胆囊动脉平滑肌细胞的电生理特性。这些细胞在暴露于高K+时收缩，平均静息电位为-36 +/- 7 mV。在电流钳下，去极化脉冲不能引起再生反应。电压钳测量表明，大部分外向电流被四乙基铵（5-10 mM）或Ca 2+通道阻断剂抑制，并且通过增加[Ca 2 +]o而增强，这表明它是Ca 2+激活的K+电流。此外，在一些细胞中观察到对细胞外Ca ~（2+）敏感的自发瞬时外向电流。在细胞贴附式膜片钳记录，钙激活的K+通道，具有117 pS的电导一致确定。在负电位（约-60 mV）下，这些单通道事件完全且非常迅速地失活，表明它们不控制健康胆囊动脉细胞中的静息膜电位。使用Ba 2+（10 mM）作为电荷载体记录的Ca 2+电流被二氢吡啶激动剂Bay K 8644增强，并被硝苯地平（0.1 μ M）阻断。只有一种类型的钙电流，L型，可以确定在这些细胞。这些结果表明，在人类胆囊动脉的主要离子电流是类似于其他哺乳动物的动脉，并表明该组织将是一个有用的模型，用于研究人类血管平滑肌中的离子电流的代谢和药理学调制。
The patch-clamp technique was used to study the electrophysiological properties of single smooth muscle cells obtained from the human cystic artery. These cells contracted on exposure to high K+ and had a mean resting potential of -36 +/- 7 mV. Under current clamp, regenerative responses could not be elicited when depolarizing pulses were applied. Voltage-clamp measurements demonstrated that a large fraction of the outward current was inhibited by tetraethylammonium (5-10 mM) or Ca2+ channel blockers and that it was enhanced by increasing [Ca2+]o, suggesting that it is a Ca2+-activated K+ current. In addition, spontaneous transient outward currents that were sensitive to extracellular Ca2+ were observed in some cells. In cell-attached patch-clamp recordings, Ca2+-activated K+ channels that had a conductance of 117 pS were consistently identified. At negative potentials (approximately -60 mV), these single-channel events deactivated completely and very quickly, suggesting that they do not control the resting membrane potential in healthy cystic artery cells. Ca2+ currents that were recorded using Ba2+ (10 mM) as the charge carrier were enhanced by the dihydropyridine agonist, Bay K 8644, and blocked by nifedipine (0.1-mu-M). Only one type of Ca2+ current, the L-type, could be identified in these cells. These results demonstrate that the major ionic currents in the human cystic artery are similar to other mammalian arteries and indicate that this tissue will be a useful model for studying the metabolic and pharmacological modulation of ionic currents in human vascular smooth muscle.