Figure 6. Gut microbiota plays an important role in the bioconversion of choline into TMAO and Ach. (A) The body weight changes after administration of choline; (B) Levels of acetylcholine and NADPH/NADP+ in the brain samples after administration of choline; (C) TMAO levels in serum and brain tissues after administration of choline mice; (D) Expression of the proteins MAOA, MAOB and COMT in liver; (E) Expression of the proteins MAOA, MAOB and COMT in brain tissues, and expression of the proteins AChE, AMP, CHRNA1 and CHRNB1 in the brain tissues. Data are presented as the means ± SD of more than 8 independent experiments, and more than 3 independent experiments in Western bolting. **p <0.05 and *p <0.01 vs. the control group by one-way ANOVA test.