Fig. 3.
Dapagliflozin effects on sodium currents in human cardiomyocytes (CMs) and human NaV1.5 channels. a Representative recordings of peak sodium currents at − 30 mV, obtained from a human atrial CM at baseline and after dapagliflozin (100 µmol/L) treatment. b NaV peak and late sodium current densities at − 30 mV, measured under baseline conditions and 5 min after administration of dapagliflozin (100 µmol/L; n/N = 17/9). P-values were derived from paired Student’s t-tests. c Representative families of sodium current traces, recorded from a human atrial CM under baseline conditions and 5 min after application of dapagliflozin (100 µmol/L). The voltage protocol is depicted as inset, d Current–voltage-relationship of NaV peak current densities in human atrial CM before and 5 min after application of 100 µmol/L dapagliflozin (n/N = 17/9; MP, membrane potential). e Left: Experimental protocol: Transiently transfected Chinese hamster ovary (CHO) cells heterologously expressing human NaV1.5 channels were plated on an NPC-384 chip. Sodium currents were recorded using the SyncroPatch 384 Automated Patch Clamp (APC) system, under baseline conditions and while exposing the cells to increasing concentrations of dapagliflozin. Right: Representative NaV1.5 current traces, recorded with APC from transiently transfected CHO cells. f Current–voltage-relationship of NaV1.5 peak current densities at baseline and after stepwise increase of the dapagliflozin concentration from 1 to 300 µmol/L (n = 8). g NaV1.5 peak current densities of the respective recordings, quantified at -20 mV (n = 8). h Activation curve of NaV1.5 channels expressed in CHO cells calculated from Boltzmann fits under baseline conditions and dapagliflozin treatment (100 µmol/L; n = 8). i Representative sodium current traces, recorded with APC from atrial- and ventricular-like hiPSC-CM under baseline conditions and after administration of increasing dapagliflozin concentrations (1, 10, 100 µmol/L). j Left: NaV peak sodium current densities relative to baseline values, recorded from atrial-like hiPSC-CM under baseline conditions and during perfusion with flecainide at increasing concentrations (1, 10, 100 µmol/L; n = 4). Right: Dose–response-curve of NaV peak current inhibition by flecainide in atrial-like hiPSC-CM (IC50 = 2.96; n = 4). k Left: NaV peak sodium current densities relative to baseline values, recorded from ventricular-like hiPSC-CM under baseline conditions and during perfusion with flecainide at increasing concentrations (1, 10, 100 µmol/L; n = 4). Right: Dose–response-curve of NaV peak current inhibition by flecainide in ventricular-like hiPSC-CM (IC50 = 3.51; n = 4). l Left: NaV peak sodium current densities relative to baseline values, recorded from atrial-like hiPSC-CM under baseline conditions and during perfusion with dapagliflozin at increasing concentrations (1, 10, 100 µmol/L; n = 8). Right: Dose–response-curve of NaV peak current inhibition by dapagliflozin in atrial-like hiPSC-CM (IC50 = 15.16; n = 8). m Left: NaV peak sodium current densities relative to baseline values, recorded from ventricular-like hiPSC-CM under baseline conditions and during perfusion with dapagliflozin at increasing concentrations (1, 10, 100 µmol/L; n = 6). Right: Dose–response-curve of NaV peak current inhibition by dapagliflozin in ventricular-like hiPSC-CM (IC50 = 29.66; n = 6). Unless stated otherwise, data are given as mean ± SEM and P-values were derived from ordinary one-way analysis of variance (ANOVA). Where indicated, the peak sodium current amplitudes were normalized to the respective cell capacitance to obtain current densities