1. To evaluate promising lead compounds for treating drug dependence through a broad panel of receptor and enzyme targets (Profile) in order to identify potential side effect liabilities and/or characterize the selectivity of the compounds for the desired pharmacological target set (Task 1). 2. To perform binding affinity and/or functional activity assessments of active compounds (Task 2). 3. To evaluate test compounds in a set of toxicological and pharmacokinetic assays in order to judge their potential for development as future therapeutic agents. These compounds and assays will be evaluated under Task 3. 4. Large compound libraries will be screened against a single target. (Task 4).