Fig. 2.

Emergence and dynamic characteristics of the isolated Ca²⁺ SR oscillator (osc.) with a simple “release-pumping-delay” mechanism in our new model of rabbit SANC (all membrane currents = 0). A: model simulations illustrating that SR can operate as a self-sustained Ca²⁺ oscillator, P_up = 20 mM/s. Note: for this and other simulations, we provide only those model parameters, which are different from our basal firing model, which is fully described in the online data supplement. B and C: results of parametric analysis for the isolated SR Ca²⁺ oscillator with simultaneously varying SR Ca²⁺ release rate and SR Ca²⁺ pumping rate are shown in terms of oscillation frequency (B) or amplitude (C). Each image shows the result of 161 × 161 = 25,921 simulations (each pixel = 5 μs⁻¹ × 0.5 mM/s) with the resultant frequency or amplitude coded by the color map shown on each image top; the parametric space yielding no sustained Ca²⁺ oscillations is shown in blue. Small green box represents the Ca²⁺ oscillator shown in A. k_s, SR Ca²⁺ release rate constant.