Fig. 6

Serotonin metabolites are affected by antibiotics in mice. a Representative images of colons stained for chromogranin A (CgA) in SPF mice without antibiotics. b Representative images of colons stained for chromogranin A (CgA) in SPF mice with antibiotics. c Representative images of colons stained for 5-HT in SPF mice without antibiotics. d Representative images of colons stained for 5-HT in SPF mice with antibiotics. e Standard curve of 5-HT in colon by ELISA. f Levels of colon 5-HT relative to total protein. Data are normalized to colon 5-HT relative to total protein in control mice. g Quantitation of CgA⁺ cell number per area of colonic epithelial tissue. h Quantitation of 5-HT⁺ cell number per area of colonic epithelial tissue. i Colonic expression of TPH1 relative to GAPDH. Data are normalized to levels in control mice. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01