The effects of β₁-adrenoceptor stimulation on activities of I-1 and PP1.

Panel A: Relative I-1 activity in ventricular myocytes in control (left bars) and upon stimulation with 1 µM isoproterenol (right bars). Experimental data for guinea pig hearts [67] are shown by black bars, simulation data with our model are shown by gray bars. Panel B: Relative PP1 activity in WT and I-1 knockout mouse hearts. Experimental data [64] are shown by black bars, our simulations – by gray bars. Experimental PP1 activity from I-1 knockout mouse hearts is normalized to 100%.