PT  - JOURNAL ARTICLE
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
TI  - Relationship between Conformational Changes in the Dopamine Transporter and Cocaine-Like Subjective Effects of Uptake Inhibitors
AID  - 10.1124/mol.107.039800
DP  - 2008 Mar 01
TA  - Molecular Pharmacology
PG  - 813--823
VI  - 73
IP  - 3
4099  - http://molpharm.aspetjournals.org/content/73/3/813.short
4100  - http://molpharm.aspetjournals.org/content/73/3/813.full
SO  - Mol Pharmacol2008 Mar 01; 73
AB  - 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