Figure 3.

Basolateral HCO₃^– uptake – effects of Cl^– and/or Na⁺ withdrawal. The figure shows representative pH_i traces. A: The rate of HCO₃^– uptake was significantly decreased in Cl-free conditions compared to standard conditions (J(B) = 73.1 ± 7.2% and 100 ± 8.5%, respectively, n = 5); B: The administration of basolateral HCO₃^–/CO₂ in Na⁺-free conditions (n = 6) greatly decreased ∆pH_i and J(B) compared to standard conditions, suggesting that a large proportion of the HCO₃^– uptake was due to a Na⁺-sensitive process, most likely NBC; C: Interestingly, the decrease in the rate of HCO₃^– uptake was obviously ameliorated in the absence of both Na⁺ and Cl^– (n  =  6) compared to the Na⁺-free condition.