FIGURE 4.

Reversal potential of glutamine-induced currents in SNAT3 mutant N76D. Oocytes were injected with 20 ng of cRNA encoding SNAT3 or its mutant N76D, and glutamine-induced (10 mm) currents were analyzed after 3–6 days of expression at pH 7.4 and 8.4. The reversal potential was recorded at three different chloride concentrations (A). The reversal potential at 9 mm chloride was extrapolated (extr.); chloride ions were replaced by gluconate ions. Wild type (wt) SNAT3 expressing oocytes did not show glutamine-induced currents in the absence of Na⁺ as shown in a typical recording (B). NMDG, N-methyl-d-glucamine.