Fig. 3.

Effect of the new experimental protocol on the shape of the pH_S trajectory and on the time to peak. A: pH_S trajectory predicted by the model when using the protocol of Somersalo et al. (22). In using this original protocol, we assume that, at the outset of the simulation, the CO₂/HCO₃⁻ is already at the plasma membrane. B: pH_S trajectory predicted by the model when using the revised protocol. Here we assume that the oocyte is initially superfused with the CO₂/HCO₃⁻-free ND96 solution until we switch the bulk solution to one containing CO₂/HCO₃⁻ and allow the CO₂ and HCO₃⁻ to diffuse to the cell surface.