Figure 1. IDO1 was increased and negatively correlated with serum 5-HT and hippocampal BDNF levels in CUMS mice. (A) Schema for chronic unpredictable mild stress (CUMS) schedule and behavioral experiments. (B–E) LC-MS detection of the TRP and 5-HT, 5-HT/TRP and KYN/TRP ratio in serum of control and CUMS groups. (F) Pearson linear correlation tests for KYN/TRP ratio and 5-HT levels in serum. n=6 mice/group. (G) Quantitative real-time PCR analysis of BDNF and IDO1 in the hippocampus. (H) Western blot analysis of BDNF and IDO1 in the hippocampus. Bars represent mean±SEM. *p< 0.05, ** p< 0.01, *** p< 0.001.