Comprehensive metabolomic characterization of the hippocampus in a ketamine mouse model of schizophrenia

Ketamine is a noncompetitive antagonist of N-methyl-D-aspartate receptors (NMDARs). We have shown that ketamine can induce cognitive impairments and schizophrenia-like symptoms in mice. However, the detailed metabolic profile changes in the progression of ketamine-induced schizophrenia-like symptoms are still not fully elucidated. In this study, an ultra-performance liquid chromatography-Q-Exactive hybrid quadrupole-Orbitrap mass spectrometry-based untargeted hippocampus high-throughput metabolomics method was first performed to screen for potential biomarkers in a schizophrenia-like state in a chronically administered ketamine-induced mouse model. Our results identified that the amino acid and energy metabolism pathways were significantly affected in mouse models of ketamine-induced schizophrenia. The detailed amino acid profiles were subsequently quantified in the hippocampus. The results showed that ketamine dramatically decreased the Lys, Gly, and Ser levels while significantly increasing the Gln level and relative Glu-to-GABA ratio. Our study suggested that Gln, Gly and Ser metabolism disturbances might be involved in ketamine-induced schizophrenia-like phenotypes. This research offers a fresh viewpoint for creating new neuroleptic medications and contributes to understanding the mechanisms underlying ketamine-induced schizophrenia.