奎尼丁对正常大鼠心室肌细胞瞬间外向钾电流的影响

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。

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

To investigate the electrophysiological characteristics of transient outward potassium current (Ito_1)in ventricular myocardial cells of normal rats and the effects of quinidine for Ito_1. the single left ventricular cell of rats was obtained by an enzymatic dissociation method. Whole cell patch clamp technique was used to record Ito_1, following the administration of quinidine.Results: ① There existed potent Ito_1 in rat ventricular myocardial cells. At 37℃, 0.2Hz and +70mV, the average peak Ito_1 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 Ito_1 intensity were reduced significantly respectively (self-control all P<0.05); the inhibitory effect of quinidine on the Ito_1 showed concentration-dependency. Conclusion:There exists potent Ito_1 in rat left ventricular cells, The peak of Ito_1 can be supressed by quinidine,this effect may be one of important role as treating Brugada syndrome.