KB—R7943改善大鼠心肌缺血—再灌注损伤室性心律失常的作用

目的：研究Na^ -Ca^ 交换抑制剂KB－R7943（2－[2-4(4-Nitrobenzyloxy)phenyl]cthyl]isothiourea methanesulphonate)对大鼠心肌缺血－再灌注损伤致室性心律失常的抑制作用。方法：制备大鼠离体左右心房，研究KB－R7943对其心肌及心率的影响，采用离体血管平滑肌张力记录不研究KB－R7943对大鼠胸主动脉血管平滑肌张力作用的影响，利用大鼠离体和在体心肌缺血－再灌注损伤（ischemia/reperfusion,I/R)致心律失常模型研究KB－R7943的抗心律失常。结果：KB－R7943对大鼠心肌收缩力、心率及血管平滑张力作用的影响均较弱，但它可有效地降低大鼠离体和在体心肌I／R后室早、室速、室颤的发生率和持续时间。结论：KB－R7943有较强的抗I／R性心律失常作用，但对大鼠正常心血管功能活动无明显影响。

Studies on KB-R7943 to Inhibit the Ischemia/Reperfusion Induced Ventricular Arrhythmias on Rats

Objective To study the effects of KB_R7943,a potent inhibitor of the Na _ exchanger, on rats to inhibit ischemia/reperfusion induced arrhythmia in comparison with that of verapamil.Methods Isolated whole atria and aorta strip were obtained from rats, the change of heart rate, tension contraction of atrial and vascular smooth muscle were recorded. KB_R7943 on ischemia/reperfusion induced arrhythmia were studied both in isolated and in anaesthetized rats.Results KB_R7943 did not depress Hr and contraction of atrial and vascular, however, it significantly attenuates the incidence and the duration of ischemic reperfused induced ventricular arrhythmia. Conclusions KB_R7943 suppresses I/R_induced arrhythmias, but there were little effects on normal cardiovascular function of rats.