Fig. 11. Steady-state pH_i of C2PLKO.1 and C2NHE2KD cells. (A) steady-state pH_i values of C2PLKO.1 and C2NHE2KD cells measured during perfusion with HEPES buffer followed by calibration with pH6.5 and pH7.0 solution gassed with O₂. (B) steady-state pH_i values of C2PLKO.1 and C2NHE2KD cells measured during perfusion with HCO₃^-/CO₂ buffer followed by calibration with pH6.5 and pH7.0 solution gassed with CO₂. Under both condition the steady-state pH_i of C2NHE2KD cells was significantly lower compared to that of C2PLKO.1 cells (n=3-4, mean ± SEM, unpaired student t-test, **p< 0.01).