Fig. 4.
Apical HCO3− efflux in wild-type and ΔF ducts luminally perfused with high Cl− or high HCO3− solution. The lumen was perfused with the high-Cl− (25 mM HCO3− and 124 mM Cl−; A) or high-HCO3− (125 mM HCO3− and 24 mM Cl−; B) solution. Cells were stimulated with forskolin and alkali-loaded with an acetate prepulse. A and B: changes in pHi in wild-type (thin line) and ΔF/ΔF ducts (thick line) with high [Cl−]L (A) or high [HCO3−]L (B). Representative traces from 6–10 experiments. C: recovery rate of pHi in wild-type (open bar) and ΔF/ΔF ducts (solid bar) with high luminal Cl− concentration ([Cl−]L) or high luminal HCO3− concentration ([HCO3−]L). Data are means ± SE. *P < 0.05, compared with wild-type ducts.