Dose-dependent effects of i.c.v. NPS on extracellular levels of dopamine in the mPFC. NPS significantly increased extracellular dopamine levels. (a) Time course of extracellular dopamine levels following central administration of saline or increasing doses of NPS. Dopamine levels were normalized to the average of four baseline samples. * p < 0.05, ** p < 0.01, *** p < 0.001, 1 nmol NPS versus saline; # p < 0.05, ## p < 0.01, ### p < 0.001, 10 nmol NPS versus saline; Bonferroni post-hoc test after significant treatment effect in two-way ANOVA. (b) Cumulative dopamine levels between 0 and 120 min post injection, calculated as area under the curve (AUC), ** p < 0.01, *** p < 0.001 versus saline; Dunnett’s post-hoc test after significant one-way ANOVA.