Fig. 8.

Influence of oxalate, in the absence of HCO₃⁻, upon I-V relationships for rabbit NBCe1-A. Oocytes were injected with either H₂O (A) or cRNA encoding rabbit NBCe1-A (B). I-V relationships were obtained by voltage clamp while the cells were sequentially exposed to a 1) Ca²⁺-free ND96 solution; 2) a modified Ca²⁺-free ND96 solution that contained 33 mM oxalate in place of 66 mM Cl⁻; and finally 3) a Ca²⁺-free 33-mM HCO₃⁻ solution that, compared with the preceding solution, contained 33 mM HCO₃⁻ + 33 mM Cl⁻ in place of 33 mM oxalate. Note that the diamonds in A are artificially offset by +3 mV from the circles to make all data sets visible. Averaged slope conductances measured between −20 and +20 mV for 6 cells are shown in C, in which the results of certain paired t-tests are shown as horizontal bars (*P < 0.05). The composition of solutions used in this protocol is shown in Table 8.