家兔陈旧性心肌梗死心室肌细胞钾离子电流的变化  

Changes of potassium currents in rabbit ventricle with healed myocardial infarction

作　　者：刘念[1] 牛惠燕[1] 李泱[1] 张存泰[1] 周强[1] 阮燕菲[1] 卜军[1] 陆再英 

机构地区：[1]华中科技大学同济医学院附属同济医院心内科,湖北武汉430030

出　　处：《中国病理生理杂志》2004年第12期2227-2231,共5页Chinese Journal of Pathophysiology

摘　　要：目的探讨陈旧性心肌梗死(HMI)心律失常的发生机制,观察HMI非梗死区心肌细胞动作电位时程(APD)、瞬时外向钾电流(Ito)、延迟整流钾电流(IK)和内向整流钾电流(IK1)的变化。方法12只家兔随机分为2组,陈旧性心肌梗死组(HMI)开胸结扎冠状动脉左回旋支,假手术组开胸但不结扎冠状动脉。3个月后应用全细胞膜片钳技术记录非梗死区心肌细胞的APD、Ito、IK和IK1。结果(1)HMI组心肌细胞的膜电容明显高于假手术组;(2)HMI组心肌细胞的APD显著延长,并有早期后除极(EAD)出现;(3)HMI组心肌细胞Ito、IK,tail和IK1的电流密度分别为(403±033)pA/pF、(114±011)pA/pF和(176±23)pA/pF,显著低于假手术组的(672±042)pA/pF、(154±013)pA/pF和(256±26)pA/pF(P<001)。结论HMI非梗死区心室肌细胞Ito、IK,tail、和IK1的电流密度的降低是其APD延长和EAD出现的离子流基础,而APD延长和EAD的出现,可能在HMI恶性心律失常的发生中起着重要作用。AIM: To elucidate the mechanism of arrhythmia in healed myocardial infarction (HMI), and to investigate the changes of action potential duration (APD),transient outward potassium current (I to ), delayed rectifier potassium current (I K) and inward rectifier potassium current (I K1 ) of left ventricular myocytes in noninfarcted zone of HMI. METHODS: 12 rabbits were randomly assigned in two groups: HMI group (thoracotomy and ligation of the circumflex coronary); sham-operated group (thoracotomy but no conorary ligation). 3 months after operation, whole cell patch clamp technique was used to record APD, I to , I K and I K1 of ventricular myocytes in non-infarcted zone. RESULTS: Membrane capacitance was larger in HMI group than that in sham-operated group. Action potential duration was lengthened significantly in HMI group and early after depolarization (EAD) appeared in HMI group. The densities of I to , I K,tail and I K1 were reduced significantly in HMI group (P<0.01), from (6.72±0.42) pA/pF, (1.54±0.13) pA/pF and (25.6±2.6) pA/pF in Sham-operated group to (4.03±0.33) pA/pF, (1.14±0.11) pA/pF and (17.6±2.3) pA/pF, respectively. CONCLUSION: The reduced densities of I to , I K,tail and I K1 in ventricular myocytes of non-infarcted zone in HMI are responsible for the prolongation of APD and the presentation of EAD, which play important roles in the malignant arrhythmia of HMI. [

关 键 词：心肌梗死 钾通道 膜片钳术 

分 类 号：R541[医药卫生—心血管疾病]