A potent inhibitor of PDE10A (IC50 = 1.26 nM for the human recombinant enzyme); selective for PDE10A over other PDEs with IC50 values ranging from 1.7 to >10 μM; increases cAMP and cGMP production as well as phosphorylation of CREB and GluR1 in mouse striatum in a dose-dependent manner; reduces apomorphine-induced climbing behavior in mice (ID50 = 0.375 mg/kg) and disrupts the conditioned avoidance response in mice and rats (ID50s = 0.441 and 1.079 mg/kg, respectively); reverses (+)-MK-801-induced deficits in prepulse inhibition and social odor recognition in rats,