INWARD RECTIFIER K+ CURRENTS IN SMOOTH-MUSCLE CELLS FROM RAT RESISTANCE-SIZED CEREBRAL-ARTERIES

被引:212
作者
QUAYLE, JM [1 ]
MCCARRON, JG [1 ]
BRAYDEN, JE [1 ]
NELSON, MT [1 ]
机构
[1] UNIV VERMONT, MED RES FACIL, DEPT PHARMACOL, 55A S PARK DR, COLCHESTER, VT 05446 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1993年 / 265卷 / 05期
关键词
POTASSIUM CHANNEL; VASODILATION; VASCULAR SMOOTH MUSCLE;
D O I
10.1152/ajpcell.1993.265.5.C1363
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
Inward rectifier K+ channels have been implicatedin the control of membrane potential and external K+induced dilations of small cerebral arteries. In the present study, whole cell K+ currents through the inward rectifier K+ channel were measured in single smooth muscle cells isolated from the posterior cerebral artery of Wistar-Kyoto rats. The whole cell K+ current-voltage relationship showed inward rectification. Inward currents were recorded negative to the K+ equilibrium potential, whereas outward currents were small. When extracellular K+ was elevated, the zero current potential shifted to the new K+ equilibrium potential, and the conductance of the inward cu''ent increased. Inward currents were reduced by external barium or cesium. Inhibition by barium and cesium increased with membrane hyperpolarization. The half-inhibition constant for barium was 2.2 muM at -60 mV, increasing e-fold for a 23-mV depolarization. We provide the first direct measurements of inward rectifier K+ currents in single smooth muscle cells and show that external barium ions are effective blockers of these currents.
引用
收藏
页码:C1363 / C1370
页数:8
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