Effect of Phenylephrin and Angiotensin Ⅱ on Reperfusion Arrhythmias in Isolated Rat Heart and Its Mechanism / 中国医科大学学报

ABSTRACT

Objective: Our aim was to investigate the effects of phenylephrine (PH) and angiotensin Ⅱ (AT) on reperfusion arrhythmias in the isolated rat heart and its mechanism. Methods: Isolated rat hearts were subjected to dual coronary perfusion. After 15 minutes of aerobic perfusion of both coronary beds, flow to the left coronary bed infused selectively into that bed. Ventricular tachycardia (VT) and fibrillation (VF) were analyzed 5 minutes after reperfusion. Results: The reperfusion arrhythmias was significantly exacerbated by PH; however, AT alone did not have the same effect. The selective Na+/H+ exchanger (NHE) inhibitor, HOE642, which was infused along with PH, reversed the proarrhythmic effects of PH. The specific protein kinase C (PKC) inhibitor GF109203X (GF) infused along with PH can only partially reverse the proarrhythmic effect of PH. The AT2 receptor inhibitor PD123319 (PD) alone increased the incidence of reperfusion-induced arrhythmias. However, no statistical significance showed. Combination of PD and AT significantly increased the incidence of reperfusion-induced arrhythmias. Conclusion: Activation of α1-adrenoceptor can exacerbate reperfusion-induced arrhythmias. The AT1 receptor activated by AT can exacerbate reperfusion-induced arrhythmias. The activation of AT2 receptor may reduce reperfusion-induced arrhythmias.