Fig. 1.

Effects of YKP1447, olanzapine, risperidone, clozapine, quetiapine and aripiprazole on dextroamphetamine-induced hyperactivity in rats. The locomotor activity of dextroamphetamine was measured every 10 min for 1 h immediately after injection of amphetamine (1.5 mg/kg, i.p.). YKP1447 (a, top left panel), olnazapine (b, top right panel), risperidone (c, middle left), clozapine (d, middle right), quetiapine (e, bottom left) and aripiprazole (f, bottom right) or vehicle (Veh), administered (i.p.) 30 min before the injection of dextroamphetamine. The locomotor activities for 1 h are expressed as the total counts. Each value is mean±S.E.M. of seven to eight rats. ^*p<0.01, compared with vehicle-vehicle group (t-test), ^#p<0.05, when compared with amphetamine control group (the post-hoc test was Dunnett's multiple comparisons test).