Figure 3
Effect of different doses of URB597 or URB694 on self-administration of peak nicotine dose and reversal of these effects by PPAR-α antagonist MK886. (a, b) The 5-day treatment with URB597 (a; 0.1–1.0 mg/kg IV) or URB694 (b; 0.03–1.0 mg/kg IV) significantly decreased the number of 30 μg/kg injections of nicotine self-administered during 1 h sessions by squirrel monkeys under a fixed-ratio 10 (FR10) schedule (sessions 4–8) compared with vehicle treatment (sessions 1–3 and 9–11). (c, d) The blockade of nicotine self-administration by URB597 (c, 1 mg/kg) or URB694 (d; 1 mg/kg) was significantly reversed by MK866 (0.3 or 1 mg/kg IM, 45 min before the session). Number of nicotine injections per 1 h session is shown over consecutive sessions. Each data point represents the mean±SEM (n=3–4). *P<0.05, **p<0.01, post hoc vs the mean of the last three sessions with vehicle pretreatment (sessions 1–3), Bonferroni test.
