Fig. 3

Effects of DAPA or INSU treatment on action potential parameters in freshly isolated cardiomyocytes. a Representative single cell action potential traces for all groups. b Action potential duration (APD) at 25, 50, 75, 90% (APD₂₅, APD₅₀, APD₇₅, APD₉₀) of repolarization are examined from DAPA or INSU treated MetS group compared to MetS and age-matched controls. The current–voltage relations (current–voltage, I–V, characteristics) of voltage-dependent Na⁺-channels (c) and L-type Ca²⁺-channels (d) for all groups. The calculated maximum current of Na⁺-channels (− 40 mV) and Ca²⁺-channels (0 mV) are given in the lower parts of the graphs as an inset. The total number of cells/group/protocol; n = 6–7. Significance level at *p < 0.05 vs. CON group and ^#p < 0.05 vs. MetS group