Figure 4.

pH_i recovery from an acid load in untransfected (Ctr) and transfected cells (pNBC1, mock) in the absence and presence of CO₂/HCO₃^-. A: in O₂/HEPES buffer, no significant difference in the pH_i recovery rate in untransfected and pNBC1-transfected cells was noted (n = 8). B: In the presence of CO₂/HCO₃^-, however, pH_i was accelerated 5-fold in transfected vs. untransfected HEK293 cells (*: p < 0.05, Student's t-test for paired samples, n = 7), indicating successful functional transfection of the pNBC1 protein. C, D: in mock-transfected vs. untransfected cells on the same slide, pH_i recovery rates were relatively low, and no significant differences were noted between mock-transfected and untransfected, or between the absence and presence of CO₂/HCO₃^-, respectively (n = 6–8).