Figure 1.

Effects of varenicline on cocaine and nicotine self-administration: each dose of cocaine or nicotine is shown above each set of bar graphs. Ordinate: the number of cocaine or nicotine injections per day for the last three days of the treatment period. Drug self-administration during saline treatment is shown as open bars. Drug self-administration during varenicline treatment is shown as gray bars (0.004 mg/kg/h) and black bars (0.04 mg/kg/h). The top row shows drug self-administration when low minimally reinforcing doses of cocaine and nicotine were available. The bottom row shows drug self-administration when higher reinforcing doses of cocaine and nicotine were available. The ANOVA found a significant effect of varenicline on self-administration of 0.0032 mg/kg/inj nicotine (F(2,6)=6.43; p=0.03) during treatment with 0.04 mg/kg/h varenicline (p=0.02). Varenicline did not significantly alter self-administration of 0.0032 or 0.01 mg/kg/inj cocaine and 0.001 mg/kg/inj nicotine (all Fs<1.73; ps=0.28–0.44). Each data point represents the mean±SEM of 3–4 monkeys. *p<0.05 vs baseline.