Effects of dipfluzine on experimental arrhythmias and cytosolic calcium concentration / 中国药理学与毒理学杂志

ABSTRACT

AIM To investigate whether dipfluzine (Dip) possesses antiarrhythmic effect on experimental arrhythmias and effect on cytosolic calcium in ventricular myocytes of guinea-pig. METHODS Experimental arrhythmias were induced by strophanthin G infusion through jugular vein in guinea-pigs and by myocardial ischemia-reperfusion (I-R) in rats respectively. Cytosolic calcium concentration ([Ca2+]i) of isolated guinea-pig ventricular myocytes was examined with laser confocal scanning microscope. RESULTSIn guinea-pigs pretreatment with Dip 20 mg·kg-1 increased the dosages of strophanthin G required to induce ventricular premature contraction (VP), ventricular tachycardia (VT), ventricular fibrillation (VF) and cardiac arrest (CA), pretreatment with Dip 10 mg·kg-1 increased the dosages of strophanthin G required to induce VP. In the I-R-induced arrhythmic model of rats, Dip 20 mg·kg-1 decreased the number of rats exhibiting VT, VF and CA, and the number of rats exhibiting VF and CA was decreased by Dip 10 mg·kg-1. Both Dip and verapamil (Ver) decreased [Ca2+]i of the ventricular myocytes in normal Tyrode′s solution. The Ca2+ overload evoked by high extracellular Ca2+ levels was inhibited by Dip and Ver, and the prophylactic effect of Dip was less than that of Ver, while the curative effect of Dip was more obvious than that of Ver. CONCLUSION Dip has antiarrhythmic effect, which is likely related to the modulation on the intracellular calcium homeostasis.