This arm plans to explore the effects of acute pre-treatment with the glucagon like peptide-1 (GLP-1) agonist, exenatide vs. placebo, on the subjective (e.g., euphoric) and behavioral effects (e.g., self-administration) of cocaine in experienced, non-treatment seeking users of the drug. We propose to study 24 subjects in a within-subject (two-day, randomized, placebo-controlled) human laboratory study of self-regulated cocaine administration. We hypothesize that acute treatment with exenatide will reduce cocaine-induced euphoria and self-regulated cocaine administration as compared to placebo

This arm plans to explore the effects of sub-chronic (5-day) treatment with exenatide as compared to placebo on the subjective (e.g., euphoric) and behavioral (self-administration) effects of cocaine in experienced, non-treatment seeking users of the drug. Upon completion of arm 1, subjects may opt to be randomized to five days of treatment with either exenatide or placebo, followed by a one-day human laboratory study of self-regulated cocaine administration. We hypothesize that subjects treated with exenatide (up to N=12) will demonstrate decreased self-regulated cocaine administration as compared to subjects treated with placebo (up to N=12).

This arm plans to explore the effects of acute pre-treatment with the glucagon like peptide-1 (GLP-1) agonist, exenatide vs. placebo, on the subjective (e.g., euphoric) and behavioral effects (e.g., self-administration) of cocaine in experienced, non-treatment seeking users of the drug. We propose to study 24 subjects in a within-subject (two-day, randomized, placebo-controlled) human laboratory study of self-regulated cocaine administration. We hypothesize that acute treatment with exenatide will reduce cocaine-induced euphoria and self-regulated cocaine administration as compared to placebo

Subjects will complete a 90 minute long "binge" cocaine self administration session (16mg/70kg). Mean inter-infusion intervals (time between cocaine boluses) will then be averaged by adding all intervals within the session and dividing by 90. Intervals during which pump access is withheld (due to increase in vital signs) will be excluded. Data on cocaine self-administration (total number of responses, infusions, and III), subjective effects, and vital signs will be checked for normality prior to analysis using Kolmogorov-Smirnov statistics and normal probability plots. The significance level for all statistical tests will be set at p<.05.