Because COX-2 inhibitors were shown to have beneficial effects in schizophrenia treatment (Zheng et al. 2017), the goal of our study was to investigate the effect of three COX-2 inhibitors: celecoxib, niflumic acid, and parecoxib on KYNA synthesis and KAT II activity in rat brain cortex in vitro. This evidence concerns the gene PTGS2 and schizophrenia.