人心房肌细胞瞬时外向钾电流的特性
Characteristics of transient outward K+ current in human atrial cardiomyocytes.
作者信息
Xu W H, Li W, Yue H W, Wang X L
机构信息
Department of Pharmacology, Peking Union Medical College, Beijing, China.
出版信息
Zhongguo Yao Li Xue Bao. 1998 Sep;19(5):481-5.
AIM
To study the properties of transient outward potassium current (Ito) in human atrial myocytes.
METHODS
The patch-clamp whole-cell recording techniques were used. When the calcium inward current was blocked by CdCl2 (0.1 mmol.L-1), the transient outward potassium current (Ito) was recorded by depolarizing cells.
RESULTS
The current was voltage dependent, it was activated quickly and inactivated rapidly too. 4-Aminopyridine (4-AP) 10 mmol.L-1 (a selective blocker of Ito) blocked the current completely. The IC50 (95% confidence limits) of 4-AP on Ito were 0.67 (0.58-0.80) mmol.L-1, 4-AP 1 mmol.L-1 shifted the activation curve of Ito to positive potential, therefore a higher membrane potential was required to activate Ito.
CONCLUSION
Ito, a major K+ channel current in human atrial cells, is blocked by 4-AP.
目的
研究人心房肌细胞瞬时外向钾电流（Ito）的特性。
方法
采用膜片钳全细胞记录技术。当用氯化镉（0.1 mmol.L-1）阻断钙内向电流时，通过使细胞去极化记录瞬时外向钾电流（Ito）。
结果
该电流具有电压依赖性，激活迅速且失活也迅速。10 mmol.L-1的4-氨基吡啶（4-AP，Ito的选择性阻断剂）可完全阻断该电流。4-AP对Ito的半数抑制浓度（IC50，95%置信区间）为0.67（0.58 - 0.80）mmol.L-1，1 mmol.L-1的4-AP使Ito的激活曲线向正电位方向移动，因此激活Ito需要更高的膜电位。
结论
Ito是人心房细胞中的主要钾通道电流，可被4-AP阻断。
Zotero 插件