In vivo microdialysis analysis of mGluR3 KO mice. Methamphetamine (MAP) induced the release of dopamine in the nucleus accumbens of mGluR3 KO mice. The extracellular dopamine levels of WT and KO mice were determined by in vivo microdialysis and HPLC. After the collection of basal fractions, MAP (2 mg/kg, i.p) was administrated at time 0. Data are given as mean (±SEM) for the indicated number of mice. Repeated-measures analysis of variance revealed a genotype effect of F1,88 = 61.9 (p < 0.001), a time effect of F8,82 = 3.74 (p < 0.01), and a genotype × time effect of F8,82 = 2.49 (p = 0.02). *p < 0.05 (Bonferroni post-hoc test).