TY - JOUR T1 - Relationship between Conformational Changes in the Dopamine Transporter and Cocaine-Like Subjective Effects of Uptake Inhibitors JF - Molecular Pharmacology JO - Mol Pharmacol SP - 813 LP - 823 DO - 10.1124/mol.107.039800 VL - 73 IS - 3 AU - Claus J. Loland AU - Rajeev I. Desai AU - Mu-Fa Zou AU - Jianjing Cao AU - Peter Grundt AU - Klaus Gerstbrein AU - Harald H. Sitte AU - Amy Hauck Newman AU - Jonathan L. Katz AU - Ulrik Gether Y1 - 2008/03/01 UR - http://molpharm.aspetjournals.org/content/73/3/813.abstract N2 - Cocaine exerts its stimulatory effect by inhibiting the dopamine transporter (DAT). However, novel benztropine- and rimcazole-based inhibitors show reduced stimulant effects compared with cocaine, despite higher affinity and selectivity for DAT. To investigate possible mechanisms, we compared the subjective effects of different inhibitors with their molecular mode of interaction at the DAT. We determined how different inhibitors affected accessibility of the sulfhydryl-reactive reagent [2-(trimethylammonium)ethyl]-methanethiosulfonate to an inserted cysteine (I159C), which is accessible when the extracellular transporter gate is open but inaccessible when it is closed. The data indicated that cocaine analogs bind an open conformation, whereas benztropine and rimcazole analogs bind a closed conformation. Next, we investigated the changes in inhibition potency of [3H]dopamine uptake of the compounds at a mutant DAT (Y335A) characterized by a global change in the conformational equilibrium. We observed a close relationship between the decrease in potencies of inhibitors at this mutant and cocaine-like responding in rats trained to discriminate cocaine from saline injections. Our data suggest that chemically different DAT inhibitors stabilize distinct transporter conformations and that this in turn affects the cocaine-like subjective effects of these compounds in vivo. The American Society for Pharmacology and Experimental Therapeutics ER -