Quipazine and CP-809101 reduce hyperactivity of En1+/Otx2 mutants in the open field. Animals were tested 15 min after IP injection of saline, 5 mg/kg quipazine, or 5 mg/kg CP-809101. (a) Quipazine specifically decreased distance traveled in the OFT for mutants (Genotype*TreatmentF1,36=8.429, p=0.006; Fisher's LSD post hoc test, p=0.001). (b) There was a significant interaction between genotype and quipazine treatment in percentages of entries into (Genotype*TreatmentF1,36=11.534, p=0.002) and the time spent in the open arms of the EPM (Genotype*TreatmentF1,36=9.286, p=0.005), with no such interaction in the number of entries into all arms (Genotype*TreatmentF1,36=1.352, p=0.254). (c) The selective 5-HT2C agonist CP-809101 reduced hyperactivity in En1+/Otx2 mutants in the OFT (Genotype*TreatmentF1,36=4.249, p=0.047; Fisher's LSD post hoc test, p<0.001). Fisher's LSD post hoc test: *p<0.05, **p<0.01, ***p<0.001.