Fig. 2.

Effect of ${\mathrm{HCO}}_3^{-}$ on apical Cl⁻ permeability in BCEC and CHO cells. A: BCEC. Both apical and basolateral compartments were initially perfused with Cl⁻- and ${\mathrm{HCO}}_3^{-}$-free Ringer solution. After the 1st apical (AP) Cl⁻ pulse, ${\mathrm{HCO}}_3^{-}$-rich Ringer solution (BR) was introduced on both sides for at least 5 min before the 2nd Cl⁻ pulse. Break in trace indicates period of wash in Cl⁻-free solution until trace stabilized (at least 5 min). B: summary data for A; all fluorescence values were normalized to the fluorescence value in the absence of Cl⁻ (F_o) obtained just before addition of Cl⁻. Calculated slopes were adjusted by any background drift in the fluorescence trace that was apparent just before addition of Cl⁻. *Significantly different from ${\mathrm{HCO}}_3^{-}$ free solution (BF) (n = 11; P < 0.05). C: CHO cells, same experiment as in A. D: summary data for C (n = 7). E: effect of 5-nitro-2-(3-phenylpropyl-amino)benzoic acid (NPPB) on ${\mathrm{HCO}}_3^{-}$-activated apical Cl⁻ permeability in BCEC. F: summary data for E. ^#Significantly different from BR (n = 8, P < 0.05).