FIGURE 4.

Simulation of sustained mitochondrial oscillations. Simulation of the integrated model of mitochondrial energetics with incorporated IMAC, ROS production, and ROS scavenging. Shown in A and C–E are the evolution of NADH and mitochondrial toward steady (i.e., a fixed-point attractor) or oscillatory (i.e., limit-cycle) states, respectively. B shows the phase-plane plot of NADH and for the steady (dashed) and oscillatory (continuous) solutions. The change from a fixed-point attractor to limit-cycle behavior was achieved simply by increasing the concentration of respiratory chain carriers, ρ^res (see the model of Cortassa et al., 2003) from 2.0 × 10⁻⁶ mM to 2.5 × 10⁻⁶ mM, while keeping all other parameters constant (shunt = 0.0533; = 0.013 μM). The other parameters used in the simulations are described in the legend of Fig. 5.