Inhibition of D-amino acid oxidase activity by antipsychotic drugs evaluated by a fluorometric assay using D-kynurenine as substrate

Abstract

A facile fluorometric assay using D-kynurenine as a substrate was utilized for evaluating the inhibition of D-amino acid oxidase (DAAO), which is one of the products of a susceptibility gene for schizophrenia, by commercial antipsychotic drugs, namely, chlorpromazine (CPZ), carbamazepine, sulpiride, quetiapine, and imipramine. CPZ inhibited DAAO (65.8± 13.2μM, n=3) as reported previously, and other drugs also inhibited DAAO activity. Among these, quetiapine had the smallest IC 50 value (19.5±2.60μM, n=3). The proposed assay can be useful for the evaluation or screening of DAAO-inhibitory drugs. © 2011 The Pharmaceutical Society of Japan.