Figure 3. Luteolin (Lut) altered the levels of the neuronal protein and intestinal motility-related biomarkers of mice with functional constipation (FC). Levels of substance P (SP) in serum (A) and colon tissue (B). Concentrations of vasoactive intestinal polypeptide (VIP) in serum (C) and colon tissue (D). Levels of acetylcholine (ACh) (E) and nitric oxide (NO) (F) in the colon. The expression of HuC/D was evaluated by immunofluorescence assay (G and H). Scale bar 50 μm. I, Western blotting analysis of inducible nitric oxide synthase (iNOS) in the colon tissue. Data are reported as means±SD (n=6). *P<0.05 and **P<0.01 (ANOVA and Tukey's multiple comparisons test).