人右心室心外膜下细胞瞬间外向钾电流的初步研究

两例终末期心脏来源于心脏移植的受体病人 ,用酶解分离法获得心外膜下 (Epi)细胞 ,在全细胞钳制条件下观察人右心室Epi细胞瞬间外向钾电流 (Ito1 )的电生理特性。结果发现 :①Epi细胞具有强大的Ito1 ,在 0 .2Hz、+70mV和 37℃条件下 ,Epi细胞的峰值Ito1 离子流强度和密度分别达 1 940± 440pA、1 2 .9± 2 .6pA/pF ;②温度对Ito1 强度的影响明显 ,在 +70mV、0 .2Hz、2 2℃和 37℃条件下 ,Epi细胞峰值Ito1 强度和密度分别为 1 1 90± 31 0pA和 7.7±1 .8pA/pF、1 960± 465pA和 1 3 .1± 2 .8pA/pF ,差异有显著性 (P均 <0 .0 1 ) ;③Epi细胞Ito1 离子流强度表现出明显的频率依赖性 ,在 37℃和 +70mV、刺激频率分别为 0 .2 ,0 .5 ,1和 2Hz时 ,Epi细胞Ito1 离子流强度分别为 1 91 0±42 0 ,1 660± 360 ,1 4 1 0± 2 50 ,830± 1 4 0pA ,差异均有显著性 (P均 <0 .0 1 )。结论 :人右心室Epi细胞存在强大的Ito1 ,此为人右心室Epi细胞复极 1期一个突出的电生理特点 ,可能是Brugada综合征等疾病所致恶性心律失常的重要离子基础之一。

Primary Study on the Transient Outward Potassium Current From the Isolated Human Right Ventricle

Two final hearts were obtained from the patients accepting heart transpl antation.By enzymatic disociation of epicardial(Epi) cells,under the condition o f whole cell patchclamp,we observed the electrophysiological characteristic of the transient outward potassium current(Ito 1) from the human right ventricula r Epi cells.Results:①There existed potent Ito 1 in human right ventricular Epi c ells.At 37℃,0.2 Hz and +70 mV test potential,the average peak Ito 1 intensity and density were 1 940±440 pA and 12.9±2.6 pA/pF respectively.②Temperature ha d obvious effect on human Ito 1.Under 0.2 Hz and +70 mV test potential,at 22℃ and 37℃,the average peak Ito 1 intensity and density were 1 190±310 pA,7.7±1 .8 pA/pF and 1 960±465 pA,13.1±2.8 pA/pF respectively (all P <0.01).③The Ito 1 showed obvious frequency dependency,i.e.,under the conditions of 37℃ an d +70 mV test potential,at 0.2,0.5,1 and 2 Hz,the average peak Ito 1 intensity were 1 910±420,1 660±360,1 410±250,830±140 pA respectively(all P <0.01).Conclusion:These outcomes indicate human right ventricular Epi cells possess pot ent Ito 1.This is one of the prominent electrophysiological characteristics of th e human right ventricular Epi cells and may be one of the important ionic bases for some malarrhythmias caused by Bragada syndrome. Chinese Journal of Ca rdiac Pacing and Electrophysiology, 2003,17(1):38～41]