A: Peak shortening amplitude of cardiomyocytes isolated from WT and APP/PS1 mouse hearts at different stimulus frequencies (0.1–5.0 Hz).

<p>Peak shortening amplitude is normalized to value obtained at 0.1 Hz of the same cell. B: Adrenergic response in cardiomyocytes from WT and APP/PS1 mice. Data are shown as percent change from baseline in the absence of adrenergic agonists, norepinephrine (NE, 1 µM) or isoproterenol (ISO, 0.1 and 1 µM). Mean±SEM, n = 13–26 cells from four to six mice per data point, * p<0.05 <i>vs.</i> WT group.