异丙肾上腺素对犬右心室肌细胞L型钙电流不均一性的影响

首都医科大学学报 ›› 2008, Vol. 29 ›› Issue (4): 471-474.

异丙肾上腺素对犬右心室肌细胞L型钙电流不均一性的影响

高颖¹, 周鹏², 刘秀兰², 杨新春²

1. 首都医科大学附属北京同仁医院心血管诊疗中心;2. 首都医科大学附属北京朝阳医院心脏中心

收稿日期:2008-03-31 修回日期:1900-01-01 出版日期:2008-08-24 发布日期:2008-08-24

Effect of Isoproterenol on Electrical Heterogeneity of L-type Calcium Current in Canine Ventricular Myocytes

Gao Ying¹, Zhou Peng², Liu Xiulan², Yang Xinchun²

1. Department of Cardiology, Beijing Tongren Hospital, Capital Medical University;2. Department of Heart Center, Beijing Chaoyang Hospital, Capital Medical University

Received:2008-03-31 Revised:1900-01-01 Online:2008-08-24 Published:2008-08-24

摘要/Abstract

摘要： 目的测定犬右心室三层心肌细胞上参与离子流平衡的内向电流L型钙电流(I_Ca.L)的特性,并研究其对异丙肾上腺素的反应.方法经酶解分离获得犬右心室外膜下细胞、M细胞和内膜下细胞,应用全细胞膜片钳技术,记录并比较不同部位心肌细胞的I_Ca.L,分析使用异丙肾上腺素前后电流-电压曲线的差异.结果 I_Ca.L的峰值电流密度(pA/pF)在右心室外膜下细胞、M细胞和内膜下细胞分别为-4.868±1.362(n=20),-3.594±0.544(n=20)和-2.874±0.547(n=20),差异有统计学意义(F=33.493,P<0.05).使用0.5μmol/L异丙肾上腺素后,右心室外膜下心肌细胞I_Ca.L的峰值电流密度由-4.832±1.127(n=11)增至-22.348±4.057(P<0.01),M细胞由-3.726±1.051(n=11)增至-17.992±4.159(P<0.01),心内膜下心肌细胞用药前后变化(-2.714±0.879,-2.987±1.012)差异无统计学意义(P>0.05).结论 I_Ca.L在犬右心室肌的不同细胞(外膜下心肌细胞、M细胞、内膜下心肌细胞)存在不均一性,β-肾上腺能激动剂可以减小右心室外膜下心肌细胞和M细胞动作电位复极1期末离子流的外向转移.

关键词: 电不均一性, L型钙电流, 全细胞膜片钳, 异丙肾上腺素

Abstract: Objective To examine the characteristic of L-type calcium current(I_Ca.L) in three distinct canine right ventricular myocytes and the response to isoproterenol.Methods Using whole-cell patch clamp techniques to examine the electrophysiological characteristics of I_Ca.L of myocytes enzymatically dissociated from canine right ventricular epicardial,midmyocardial,and endocardial,and to study the difference of current-voltage relations before and after using isoproterenol.Results The peak density of I_Ca.L(pA/pF) was-4.868±1.362(n=20),-3.594±0.544(n=20),-2.874±0.547(n=20)(F=33.493,P<0.05) in right ventricular(RV) epicardial,midmyocardial,and endocardial myocytes(P<0.01),respectively.Perfusion of Iso(0.5 μmol/L) increased peak I_Ca.L densities from-4.838±1.127(n=11) to-22.348±4.057(P<0.01) in RV epicardial myocytes,-3.726±1.051(n=11) to-17.992±4.159(P<0.01) in RV midmyocardial myocytes,-2.714±0.879(n=10) to-2.987±1.012(P>0.05) in RV endocardial myocytes.Conclusion Iso can significantly increase I_Ca.L densities peak on the Epi cells and M cells,but M cells and the Endo cells present no response to the drug.β-adrenergic agonists can reduce outward shift in the current active at the end of phase 1 of the right ventricular epicardial action potential.

Key words: electrical heterogeneity, L-type calcium current, whole-cell patch clamp, isoproterenol

中图分类号:

Q424

高颖;周鹏;刘秀兰;杨新春. 异丙肾上腺素对犬右心室肌细胞L型钙电流不均一性的影响[J]. 首都医科大学学报, 2008, 29(4): 471-474.

Gao Ying;Zhou Peng;Liu Xiulan;Yang Xinchun. Effect of Isoproterenol on Electrical Heterogeneity of L-type Calcium Current in Canine Ventricular Myocytes[J]. Journal of Capital Medical University, 2008, 29(4): 471-474.

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