Figure 1.

A, Intracerebroventricular administration of NPS induced cocaine-seeking behavior. SA, Mean of the 3 last days of self-administration; Ext, mean of the 2 last days of extinction. The highest dose of NPS significantly increased lever pressing in the absence of cocaine (N = 8; p = 0.002). B, The highest dose of NPS did not increase lever pressing in drug-naive mice (N = 6). The data are represented as means ± SEM. Statistical significance was calculated by ANOVA and Bonferroni's corrections were made for the subsequent pairwise comparisons such that significance was set at p < 0.0125. *Significant versus saline.