Figure 4.

Wild-type (WT) mice and serotonin 2C (5-HT_2C) knockout (KO) mice showed comparable levels of baseline locomotion and were equally affected by clozapine treatment of 5 mg/kg (a). In 5-HT_2A KO mice, olanzapine produces a similar effect to that observed following clozapine, with WT mice demonstrating reduced locomotor behavior relative to saline-treated animals, while 5HT_2A KO mice are resistant to this effect (b). Scopolamine (c) and diphenhydramine (d) both produced an increase in locomotion that was not dependent on 5-HT_2A receptor signaling. Data are shown as mean±SEM. ^**P<0.01, ^***P<0.0001 difference from vehicle treatment. ^###P<0.0001 indicates a significant difference in behavior of the KO relative to WT mice under the same treatment regimen.