Fig. 8.

AMPH stimulated DA efflux in hDAT- and T62D-hDAT cells in the presence and absence of Zn²⁺. T62D-hDAT cells were loaded with 5 μM DA as described under Materials and Methods in the presence of 30 μMZn²⁺, and hDAT cells were loaded in the absence of Zn²⁺ at 37 °C for 30 min. AMPH-stimulated DA efflux was measured by superfusion as described under Materials and Methods in either the presence (▪, hDAT; ▪, T62D-hDAT) or absence of Zn²⁺ (□, hDAT; ○, T62D-hDAT) of 30 μM Zn²⁺ as indicated (n = 3). Baseline values of [³H]DA were collected for 70 min until the addition of 10 μM AMPH (arrow). Initial levels of DA in the cells were the following: T62D-hDAT without Zn²⁺, 3.8 ± 0.9 nmol/mg protein; T62D-hDAT with Zn²⁺, 12.2 ± 1.6 nmol/mg protein; hDAT without Zn²⁺, 10.5 ± 0.3 nmol/mg protein; hDAT with Zn²⁺, 11.8 ± 0.6 nmol/mg protein. In two-way ANOVA analysis, p < 0.0001 for time (fraction) and the mutant/Zn²⁺ condition; p < 0.0001 for the interaction; ^*, p < 0.01 for hDAT with Zn²⁺ versus all other groups. T62D-hDAT with no Zn²⁺ differed from all other groups at p < 0.001. There was no statistical difference between hDAT with no Zn²⁺ and T62D-hDAT with Zn²⁺.