Fig. 4.
Peak shortening (PS) amplitude of cardiomyocytes from young or old wild-type (WT) and AMPK deficient KD mice at different stimulus frequencies (0.1 – 5.0 Hz). (A) Absolute peak shortening (normalized to resting cell length) amplitude at various stimulus frequencies; (B) Normalized PS value at various stimulus frequencies (PS was shown as % change from PS value obtained at 0.1 Hz from the same cell). Mean ± SEM, n = 17 – 24 cells from 5 mice per group, *p < 0.05 vs. WT-young group, **p < 0.05 vs. respective baseline value (0.1 Hz).