FIGURE 8.

Sodium-dependent transient currents and GABA-induced steady-state currents. The membrane voltage of oocytes expressing GAT-1-WT or the indicated mutants was stepped from a holding potential of −25 mV to voltages between −140 to +60 mV in 25-mV increments. Each potential was held clamped for 500 ms, followed by 500 ms of a potential clamped at −25 mV. For each condition, the traces shown are from the same oocytes that are representative of at least three repeats: NaCl, absolute (unsubtracted) currents in ND96; NaCl-ChCl, currents in nominal sodium-free medium (choline substitution) were subtracted from those in ND96; and GABA-induced, currents in ND96 were subtracted from those in the same medium supplemented with 1 mm (GAT-1-WT) or 10 mm (Q291N and Q291S) of GABA. The dashed lines indicate no current.