Figure 1. Effects of basolateral or luminal HCO₃⁻/CO₂ on intracellular pH.

Initially the bath and lumen of guinea-pig pancreatic duct segments were separately perfused with the standard HCO₃⁻/CO₂-free Hepes-buffered solution. Thereafter, in A(representative of 5 experiments), first the luminal perfusate and then the bath solution was switched to a HCO₃⁻-buffered solution containing 25 mm HCO₃⁻-5 % CO₂ (filled bar). In B (representative of 4 experiments), the luminal and bath solutions were switched first to 25 mm HCO₃⁻-5 % CO₂ (filled bar) and then to 25 mm HCO₃⁻-0 % CO₂ (open bar).