奎尼丁对正常大鼠心室肌细胞瞬间外向钾电流的影响

The Effect of Quinidine for the Transient Outward Potassium Current of Ventricular Myocardial Cells in Normal Rats.

研究大鼠心室肌细胞瞬间外向钾电流(Ito1)的特性及奎尼丁对其的影响,从而从细胞离子的层面去探讨奎尼丁作为治疗Brugada综合征的侯选药物的机制。用酶解法分离大鼠单个左室细胞,应用膜片钳全细胞方法记录Ito1,观察不同浓度的奎尼丁对心室肌细胞Ito1的作用。结果:①大鼠心室肌细胞具有强大的Ito1,在0.2Hz,+70mV和32℃条件下,其平均峰值Ito1强度和密度分别为1940±440pA和12.9±2.6pA/pF;②在奎尼丁1,2.5,5,7.5,10μmol/L不同的浓度下,奎尼丁抑制Ito1程度越明显(自身对照P<0.05),其作用呈浓度依赖性。结论:奎尼丁可以通过抑制Ito1,延长动作电位的复极时程,此很有可能是其作为治疗Brugada综合征的侯选药物的机制之一。

To investigate the electrophysiological characteristics of transient outward potassium current （ Ito1 ） in ventricular myocardial cells of normal rats and the effects of quinidine for Ito1. the single left ventricular cell of rats was obtained by an enzymatic dissociation method. Whole cell patch clamp technique was used to record Ito1 , following the administration of quinidine. Results ： ① There existed potent Ito1 in rat ventricular myocardial cells. At 37℃, 0.2Hz and ＋ 70mV, the average peak Ito1 intensity and density were 1940 ±440 pA and 12.9 ＋ 2.6 pA/pF respectively. ② When 1,2.5,5,7.5,10 μmoL/L Quinidine added, the average peak Ito1 intensity were reduced significantly respectively （self-control all P 〈0.05） ; the inhibitory effect of quinidine on the Ito1 showed concentration-dependency. Conclusion：There exists potent Ito1 in rat left ventricular cells, The peak of Ito1 can be supressed by quinidine ,this effect may be one of important role as treating Brugada syndrome.