Fig. 4.

Effect of tryptophan on 5-HT metabolic pathway in the hypothalamus of chronically stressed mice

Tryptophan-targeted metabolomics analysis (A) PCA plot; (B) Z_score plot; Serum box plots of (C) tryptophan; (D) 5-hydroxytryptophan; (E) kynurenine; (F) The content of 5-HT in the mice colon was detected by ELISA; (G) RT-qPCR was used to detect the expression of tph1 in the mice colon, (H) The content of 5-HT in the mice cortex was detected by ELISA; (I–L) RT-qPCR was used to detect the expression of tph2 in the mouse cortex, and tph2、5-HT_1B and 5-HT_2C mRNA in the mice hypothalamus. Values are expressed as mean ± SEM. *P < 0.05, **P < 0.01. Significant differences between means were determined by t-test or one-way ANOVA and Tukey's multiple comparison test.