FIGURE 4.

Distributions of open times predicted by the IP₃R channel model. (A) Open-time distributions for basal Ca²⁺ concentrations at [Ca²⁺] = 0.2, 2, and 50 μM with [IP₃] = 10 μM. Open symbols are results of stochastic simulations, and solid curves were obtained from the transition matrix theory. (B) Distributions of channel open durations involving A3-only and A4-related openings, derived from stochastic modeling at [Ca²⁺] = 0.2 μM and [IP₃] = 10 μM.