FIGURE 5.

Mitochondrial Ca²⁺ level after changes in cytoplasmic Ca²⁺. (A) The behavior of the whole model is studied with the AUTO 97 software as a function of cytoplasmic Ca²⁺ concentration, [Ca²⁺]_i. The simulations were performed with the following set of parameters: (pull): ρ^RES = 0.00072 mM, ρ^F1 = 1.216 mM, s⁻¹, s⁻¹, and mM s⁻¹, and (push): ρ^RES = 0.0036 mM, ρ^F1 = 0.0522 mM, s⁻¹, s⁻¹, and mM s⁻¹. Curve a is obtained with the same parametric set as “pull” except for mM s⁻¹. Otherwise the concentration of AcCoA is 1.0 mM, and the catalytic constants of CS and MDH are s⁻¹ and s⁻¹, respectively. (B) Experimental results redrawn from McCormack et al. (1990) showing the accumulation of mitochondrial Ca²⁺ in the absence (curve I) or in the presence of Na⁺ (curve II).