Figure 3. Changes in key variables in the perfused duct model evoked by cAMP stimulation and exposure to high luminal HCO₃ ⁻ concentration.

Time course of changes in intracellular Cl⁻ concentration ([Cl⁻]_c) (A), basolateral membrane potential (E _bl) (B) and intracellular pH (pH_c) (C). The lumen is perfused initially with the normal HCO₃ ⁻ solution (containing 25 mm HCO₃ ⁻ and 124 mm Cl⁻). At 10 and 40 min, the luminal perfusate is switched to a high‐HCO₃ ⁻ solution (125 mm HCO₃ ⁻ and 24 mm Cl⁻) for 10 min. Transporter activities are altered from 30 min to represent cAMP stimulation. The solid and dashed lines show the slightly different predictions for the 1:2 and 1:1 Cl⁻:HCO₃ ⁻ stoichiometries of the SLC26A6 exchanger.