Fig. 2.

Reduced DAT activity in KO compared with WT mice. KO mice showed significantly less DA uptake (A) and AMPH-stimulated DA efflux (B) from striatal synaptosomes than WT mice. A, striatal synaptosomes from WT and KO mice were incubated with various concentrations of [³H]DA for 1 min at 37°C. The V_max value for [³H]DA uptake was significantly lower in KO mice than in WT mice (Student's t test, p < 0.05, n = 6), whereas there was no difference in K_m values. B, striatal synaptosomes from WT and KO mice were perfused (37°C) for 20 min with KRB at a speed of 450 μl/min before sample collections (2 min interval). Then, 1, 10, and 100 μM AMPH were introduced to the synaptosomes at fraction numbers 2, 8, and 14, respectively, and KRB was perfused for the rest of the fractions. A two-way ANOVA indicated a significant genotype effect [F(1,191) = 5.18, p < 0.01]. Post hoc Bonferroni analysis indicated that a significant reduction in AMPH induced DA efflux at fractions 3, 4, 9, 10, 15, and 16. ^*, p < 0.05; ^**, p < 0.01 WT versus KO. Data are represented as mean ± S.E.M.