Effect of polyamines on intracellular calcium of the rat cardiomyocytes with anoxia and reoxygenation

AIM: To study the effect of extrogenous low concentration polyamine on cardiomyocyte calcium overload caused by anoxia and reoxygenation. METHODS: Enzymatically isolated rat ventricular myocytes were perfused with normal Tyrode solution for 8 min, then change to anoxia solution for 32 min, at last back to normal Tyrode solution perfusion for 8 min to establish the cardiomyocyte model of anoxia and reoxygenation. Spermine was added extracellularly to the bath before anoxia and spermine, spermidine or putrescine was added extracellularly after reoxygenation. Intracellular calcium fluorescence intensity (FI) was measured continuously by laser scan confocal microscope (LSCM). RESULTS: In the unstimulated state, exogenous spermine (1 mol/L) did not change resting ［Ca2+］i in the rat cardiomyocytes. Adding spermine before anoxia antagonized the ［Ca2+］i elevating caused by anoxia/reoxygenation. Adding spermine after reoxygenation also lowed the enhanced ［Ca2+］i caused by reoxygenation. Considering the potency of two conditions, the former was more efficacious than the later. Spermidine and putrescine also lowed the enhanced ［Ca2+］i caused by reoxygenation, but they were less efficacious than spermine. CONCLUSIONS: The results indicate that spermine given before anoxia or after reoxygenation, antagonized or lowed the cardiomyocytes calcium overload caused by anoxia/reoxygenation, but the later was weaker than the former. The order of potency of the polyamine lighten cardiomyocytes calcium overload caused by anoxia/reoxygenation was spermine>spermindine>putrescine.