Electrophysiological changes in rat ventricular myocardium at different stages of experimental diabetes / 中国病理生理杂志

ABSTRACT

AIM: To explore the probable mechanisms of diabetes-induced arrhythmias. METHODS: Diabetes was induced in male SD rats,using a single injection of alloxan into tail vein. Untreated age-matched animals were used as controls. All animals were observed by 2,4,6 and 8 weeks,respectively. Transmembrane potentials were recorded with conventional glass microelectrodes. RESULTS: Action potential duration(APD) at all level (APD10,APD20,APD30,APD50,APD70,APD90) was significantly lengthened in right ventricular papillary muscle from week 2 of diabetes. At week 8,APD was more lengthened at any level of repolarization than that at week 2. No differences were observed in the maximum rate of depolarization(V_ max ),overshoot(OS) and action potential amplitude(APA) as well as the resting membrane potential(RP) from the 2th to 8th week of diabetes. CONCLUSION: The results indicate that prolongation of APD may be prominently responsible for the increased incidence of cardiac re-entry-arrhythmias and sudden death,especially at late stages of diabetes.