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  

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

作　　者：高颖[1] 周鹏[2] 刘秀兰[2] 杨新春[2] 

机构地区：[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

出　　处：《首都医科大学学报》2008年第4期471-474,共4页Journal of Capital Medical University

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(ICa.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ICa.L,分析使用异丙肾上腺素前后电流-电压曲线的差异。结果ICa.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ICa.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ICa.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。Objective To examine the characteristic of L-type calcium current （ICa.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 ICa.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 ICa.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 ICa.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 ICa.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.

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 

分 类 号：Q424[生物学—神经生物学]