Acquisition of action potential
Spontaneously-beating clusters hiPSC-CMs were used to record action potentials (APs) in current-clamp mode (Free gap mode). The intracellular solution contained (in mmol/L): 150 KCl, 1 MgCl2, 10 EGTA, 5 ATP Na2 and 5 Hepes. Adjusted the pH to 7.2 with KOH. The external solution contained (in mmol/L): 135 NaCl, 4 KCl, 1.8 CaCl2, 1 MgCl2, 10 C6H12O6 and 5 Hepes. Adjusted the pH to 7.4 with NaOH. Data were analyzed by ABF Utility and MiniAnalysis software. APs were filtered at 2.9 kHz and digitized at 100 Hz respectively.