人右心室心外膜下细胞瞬间外向钾电流的初步研究

Primary Study on the Transient Outward Potassium Current From the Iso lated Human Right Ventricle.

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。

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]