Figure 2.

Functionally impaired DAT variants display alterations in psychostimulant interactions. Competition [³H]dopamine uptake curves with indicated concentrations of amphetamine (A), methylphenidate (B), or cocaine (C), carried out on transiently transfected COS-7 cells expressing DAT WT or a coding DAT variant. Curves are presented as means ± S.E. of three experiments, each normalized to control without inhibitor present. I312F shows decreased apparent amphetamine affinity but significantly increased apparent affinity for methylphenidate and cocaine (see Table 2). T356M displays a loss of apparent affinity for all three DAT ligands, though particularly pronounced for methylphenidate and cocaine. The dopamine uptake mediated by D421N was too low to allow meaningful data fitting.