Figure 6. Changes in [Cl⁻]_i on modifying basolateral Cl⁻ concentration.

A, initially the bath and lumen of the duct segments were perfused with the standard HCO₃⁻-buffered solution. The basolateral perfusate was then switched to the low Cl⁻-high HCO₃⁻ solution in the absence and presence of forskolin (1 μm). One of five experiments. B, with the bath and lumen initially perfused with the standard Hepes-buffered solution, the luminal perfusate was switched to the 0 Cl⁻ Hepes-buffered solution in the absence and presence of forskolin (1 μm). One of four experiments. C, with the bath and lumen initially perfused with the HCO₃⁻-buffered solution, the basolateral membrane was pretreated with H₂DIDS (200 μm) and then the basolateral perfusate was switched to the low Cl⁻-Ihigh HCO₃⁻ solution in the presence of forskolin (1 μm). One of four experiments.