Dose–response effects of 5-HT_2C receptor ligands on basal DA release in the striatum and the nucleus accumbens. The inverse agonist SB 206553 (a, b), the antagonist SB 242084 (c, d), and the agonist Ro-60–0175 (e, f) and their corresponding vehicle (v) were administered intraperitoneally (doses in milligrams per kilogram) as indicated by vertical arrows. Data represent mean ± SEM percentages of baseline in each sample (time courses) or averaged over 2.5 hr monitoring (Insets: doses in milligrams per kilogram indicated in histograms or below) (n = 4–6 animals/group). *p < 0.05, **p < 0.01, and ***p < 0.001 versus the vehicle group (Fisher's PLSD test).