GAT1 knockout (KO) mice show locomotor hyperactivity and increased sensitivity to psychotomimetic drugs in the open field test.

<p><b><i>A1</i></b>, Total distance traveled of wild-type (WT) and knockout (KO) mice in 30-min tests. <b><i>A2</i></b>, Distance traveled of WT and KO mice in each 5 min within the 30-min tests. <b><i>A3</i></b>, Total distance traveled of WT and KO in 30-min tests repeated daily for 4 days. n = 8–9 for each genotype. ** <i>p</i><0.01, *** <i>p</i><0.001 vs WT, ANOVA. <b><i>B</i></b> and <b><i>C</i></b>, To test the stimulant effects of NMDAR antagonist MK801 and phencyclidine (PCP), mice were injected i.p. with drug after 30-min acclimation in the open field, and then immediately tested for another 30 min. Locomotor hyperactivity could be induced by MK801 and PCP. GAT1 KO mice showed increased sensitivity to MK801 and PCP. <b><i>B1</i></b>, <b><i>B2</i></b>, <b><i>C1</i></b> and <b><i>C2</i></b>, Distance traveled of WT and KO mice in each 3 min within 1 h tests. <b><i>B3</i></b> and <b><i>C3</i></b>, Distance traveled of WT and KO mice in 30-min tests after drug administration. n = 6–8 for each group. * <i>p</i><0.05, ** <i>p</i><0.01 vs saline, ANOVA.