Fig. 2
Current traces of ICa.L, ICa.T and hyperpolarization-activated inward current (If) in P19-derived cardiomyocytes and Effects of MAPK inhibitors. a Representative current traces of ICa.L, ICa.T and If from a single isolated beating cardiomyocytes derived from P19 cells on differentiation day 14 with vehicle (control). ICa.T was recorded by subtracting the current traces obtained by VHP of − 50 mV from the current traces obtained by VHP of − 100 mV. If was obtained from VHP of − 40 mV to various test potentials ranging from − 50 to − 140 mV in 10 mV increment. b–d Representative current traces of ICa.L, ICa.T and If in P19-derived cardiomyocytes on differentiation day 14 in the presence of 10 μM PD98059 (b), 10 μM SP600125 (c), and 10 μM SB203580 (d). e–g The graphic representation of the current (I)–voltage (V) relationships of ICa.L (a), ICa.T (b), and conductance (G)–voltage (V) relationship of If (g). h The maximum chord conductance of ICa.L (Gmax, Ca.L) obtained at the potential range from + 20 mV to + 40 mV. i The maximum chord conductance of ICa.T (Gmax, Ca.T) obtained at the potential range from − 10 mV to + 10 mV. j The maximum chord conductance of If (Gmax, f) obtained at the potential range from − 120 to − 150 mV. Current amplitude of ICa.L and ICa.T were assessed by means of time-dependent components of each trace. *p < 0.05 vs. control, **p < 0.01 vs. control. Filled circle, control (n = 17–37); filled square, 10 μM PD98059 (n = 12–17); filled upward triangle, 10 μM SP600125 (n = 9–11); filled downward triangle, 10 μM SB203580 (n = 21–27)