Fig. 12.

Cl⁻ dependence, DIDS sensitivity, and Na⁺ independence of intracellular alkalinization in AeAE oocytes. A: representative recordings of pH_i and membrane potential (V_m) in an AeAE oocyte exposed to a 5% CO₂/33 mM HCO₃⁻ solution (solution III, Table 2) for 2 h prior. Extracellular concentrations (in mM) of Cl⁻ and DIDS are indicated. When extracellular [Cl⁻] was lowered, it was replaced by gluconate. Solution changes are indicated by dashed vertical lines. Intervals a–d in the pH_i trace indicate the intervals where rates of pH_i change (ΔpH_i/Δt) were measured. B: representative recordings of pH_i and V_m in a H₂O-injected oocyte, using a protocol similar to that described in A. C: summary of ΔpH_i/Δt measurements. Shaded bars represent ΔpH_i/Δt values of AeAE oocytes (number of oocytes shown in parentheses) during the intervals identified in A. The open bars represent H₂O-injected oocytes at similar intervals. Values are means ± SE. Brackets connecting shaded and open bars represent comparisons in unpaired t-tests resulting in significant differences (***P < 0.001). ^a,bP < 0.001, categorization of the means of the AeAE oocytes as determined by a repeated-measures ANOVA and Newman-Keuls posttest. D: representative recording of pH_i in an AeAE oocyte that examines the Na⁺ dependence of AeAE transport. Extracellular concentrations (in mM) of Cl⁻ and Na⁺ are indicated. A total of 6 AeAE oocytes were evaluated using this protocol.