Fig. 6

SANLCs induced by the BMP4/PD/BMS (BPM) possess typical electrophysiological characteristics of SAN. a Spontaneous beating frequency of SANLCs was significantly higher in the BPM (n = 6) than in the GiWi groups (n = 6) (t test, ***p < 0.001 versus GiWi control followed by Bonferroni’s post hoc test). b HCN4 channel inhibitor treatment caused significantly decreased beating rate in the BPM (n = 7) compared to the GiWi groups (n = 7) (t test, **p < 0.01 versus GiWi control followed by Bonferroni’s post hoc test). c Representative ventricule-like, atria-like, and sinus node-like action potential (AP) curves were recorded by whole cell patch clamp (left panel). The percentage of cells with pacemaker-like AP was remarkably increased in the BPM compared to the GiWi group (6/18 versus 2/15, BPM versus GiWi) (t test, ***p < 0.001 versus GiWi control). Data are presented as “mean ± SD”