Administration of Cariprazine (30 µg/kg) reduces the striatal uptake of both radioligands to the level of nonspecific binding compared with baseline PET measurements. Cariprazine has negligible effect on the time-activity curves in the cerebellum. At doses of 5.0 and 30 µg/kg, Cariprazine causes a dose-dependent dopamine D2/D3 receptor occupancy of ~45% and ~80% for both antagonist [C] raclopride and agonist radioligand [C]MNPA. Receptor occupancy of dopamine D2/D3 receptors calculated using the transient equilibrium and the MRTM2 methods ranged from 5% at the lowest dose (1.0 µg/kg) to 94% at the highest dose (300 µg/kg). The effects of 5 doses of Cariprazine (ranging from 0.005 to 0.15 mg/kg) are examined on EPM behavior of wild-type mice. Whereas lower doses of Cariprazine (0.005 to 0.02 mg/kg) do not alter the time spent in open arms, the two higher doses (0.08 and 0.15 mg/kg) lead to a significant decline of this measure (ANOVA, (F(5,52)=4.20; p=0.0032)). Moreover, the two higher doses of Cariprazine also lead to a significant decrease in the total number of arm entries (F(5,52)=7.21; p=0.0001)) but this decrease in the total number of arm entries is largely accounted for by a significant decrease in the number of closed arm entries (F(5,52)=11.75; p=0.0001)). The two highest doses of Cariprazine (0.08 and 0.15 mg/kg) have significant effects on locomotor activity, but doses ranging from 0.005 to 0.02 mg/kg do not affect anxiety-like behavior or locomotor activity in the EPM test. A significant (P<0.01) reduction in ouabain-induced hyperactivity is observed after acute i.p. administration of all doses of Cariprazine (mean±SEM: 0.06 mg/kg, 64.2±3.88; 0.25 mg/kg, 72.7±11.67; 0.5 mg/kg, 40.6±5.32; 1 mg/kg, 19.5±8.78) and lithium (40.4±12.78), compared with ouabain injection alone (114.6±14.33). The highest Cariprazine dose produced significant sedation (72% inhibition for Cariprazine 1.0 mg/kg aCSF vs. saline aCSF; P<0.05).