Figure 3. Spatial propagation of ΔΨ_m depolarization in non-oscillating mitochondrial networks using the 1D RD-RIRR model.

A network consisting of a row of 17 mitochondria was analyzed. The mitochondrion in the center (mito_9) was initialized with parameters within the oscillatory domain (shunt = 0.14) whereas the other mitochondria were within the nonoscillatory stable range of parameters (shunt = 0.02). etSOD was 1.45 µM for all mitochondria in the network. A and B) The dynamics of ΔΨ_m and O₂ ^.− _i without O₂^.− coupling through diffusion between mitochondria (i.e., D _O2 ^.− _i = 0). Mitochondria in the row are differentiated by colors, and only part of one side of the row is shown (i.e., from mito_9 to mito_17). C) ΔΨ_m dynamics in the presence of O₂^.− diffusion (D _O2 ^.− _i = 4×10⁻⁹ cm² s⁻¹). D and E) Expanded records of the third depolarization (D) and repolarization (E) waves spanning mito_9 through mito_17. F) Expanded record of O₂^.− during a repolarization wave showing the dynamics of O₂ ^.− _i in each mitochondrion (color coded) with mito_9 showing the highest amount of cytoplasmic O₂ ^.−. G and H) The rate of O₂^.− release from mitochondria to the periplasmic space (Vt _O2 ^.− _i) in the network (G) or in an isolated mitochondrion (H). All other parameters were as described in [16] and also listed in the Supplemental Materials (Table S2).