[3H]dopamine uptake in rat brain synaptosomes. Effect of d-amphetamine and d-pseudoephedrine on [3H]dopamine uptake in rat striatal (n = 8) and nucleus accumbens (n = 4) synaptosomes. IC50 is defined as the concentration of drug producing a 50 percent inhibition in 1 nM [3H]dopamine uptake. Values represent uptake as percentage of control. IC50 values are mean ± S.E.M. from duplicate samples in each independent experiment. The IC50 values of amphetamine in inhibiting [3H]dopamine uptake in striatum and nucleus accumbens are 4.28 ± 0.47 and 2.95 ± 0.42 μM, respectively, and of d-pseudoephedrine in inhibiting [3H]dopamine uptake in striatum and nucleus accumbens are 667 ± 126 and 530 ± 61 μM, respectively.