Neonatal cardiomyocyte expressing α-actinin–YC-Nano140 showing contractions in response to electric field stimulation. Stimulation performed at 5 Hz. Epifluorescence observation. Left, ECFP fluorescence (cyan); right, Venus fluorescence (yellow). Objective lens, 60×. Video speed, 33 fps. Bar, 10 µm. See Fig. 5 for details.
