The presence of nifedipine in culture medium inhibits differentiation of ES cell-derived CMs.

(A) Protocol used to determine the effect of nifedipine application during cell differentiation. Note that for beating EBs and single cell electrophysiology and Ca2+ imaging experiments, analysis was performed at least 24 hours after washout to reflect long-term changes instead of acute drugs effects. (B–C) Representative experiments showing EBs with GFP expressing areas cultured under control conditions (B) and after nifedipine-treatment (10 µM) (C) of ES cells. (D–F) Representative EBs showing EGFP+ CMs differentiated of ES cells under control conditions (D), after nifedipine- (E) and BayK8644- (F) treatment. (G) Representative FACS analysis of ES cell-derived CMs generated under control, nifedipine- and BayK8644-treated conditions. (Scale bars 50 µm (B, C) and 20 µm (D–F).