Effects of verapamil preconditioning on cardiac function in vitro and intracellular free Ca~(2+) and L-type calcium current in rat cardiomyocytes post ischemia-reperfusion injury
10.3760/cma.j.issn.0253-3758.2010.03.006
- VernacularTitle:心肌缺血再灌注损伤和维拉帕米预处理对大鼠心功能和心肌细胞内钙荧光强度以及L型钙电流的影响
- Author:
Wei YU
1
;
Jing-Jing WANG
;
Wen-Yun CAN
;
Guo-Sheng LIN
;
Cong-Xin HUANG
Author Information
1. 武汉大学人民医院
- Keywords:
Verapamil;
Myocardial ischemia;
Reperfusion injury;
Calcium
- From:
Chinese Journal of Cardiology
2010;38(3):225-229
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the influences of verapanal preconditioning on cardiac function in vitro and intracellular free Ca~(2+) and L-type calcium current (I_(Ca-L)) in rat cardiomyocytes post ischemiareperfusion (I/R) injury. Methods The isolated rat hearts in control group (37 ℃ Tyrode solution perfusion for 30 min, n =6), I/R group ( no flow for 30 min followed 30 min reperfusion with 37 ℃ Tyrode solution, n =7) and verapamil preconditioning group [37 ℃ Tyrode solution perfusion for 10 min, adding verapamil (20 μmol/L ) to Tyrade solution and perfusion for another 30 nan, followed then by 30 min no flow and 30 min reperfusion, n=7 ] using Langendorff perfusion system. The fluorescence intensity of intracellular Ca~(2+) was detected with Fluo-3/AM loading by the laser scanning confocal microscope. The I_(Ca-L) was recorded via whole-cell patch clamp technique in enzymatically dissociated single rat ventricular myocytes. Results As expected, arrhythmias and cardiac dysfunction were shown post I/R injury. The fluorescence intensities of intracellular free Ca~(2+) in cardiomyocytes were significantly increased compared with control group (P <0. 01 ). By voltage clamp protocol, peak current densities of I_(Ca-L) was significantly reduced and I-V curve significantly elevated. Post I/R injury compared with control group (P < 0. 01 )which could be reversed by Verapamil preconditioning. Verapamil preconditioning also significantly improved diastolic and systolic functions, and reduced the incidence of arrhythmias. Conclusions Myocardial I/R injury might significantly impair heart functions and induce arrhythmias via cellular Ca~(2+) overload.Verapamil preconditioning could prevent heart I/R injury and reduce arrhythmias by decreasing influx of I_(Ca-L), thereby stabilizing cardiomyocytes in myocardial stunning and avoiding occurrence of Ca~(2+) -induced Ca~(2+) release during I/R injury.
