Fig 1.
Luminal 5-HT concentrations in the colons of EX-GF mice.
(A) Standard peaks of 3,4-dihydroxy-phenylacetic acid (DOPAC), dopamine (DA), 5-hydroxyindole acetic acid (5-HIAA), isoproterenol (ISO) and 5-HT in 0.02 M acetate buffer including 10 μM EDTA-2Na. (B) Representative chromatogram of the luminal contents of the colon. The 5-HT peak is indicated by arrows.
Fig 2.
Luminal and tissue 5-HT concentrations in the gastrointestinal tract of germ-free (GF) mice and GF mice reconstituted with SPF mouse feces.
(A) GF and EX-GF mice were sacrificed at 10 weeks of age. Luminal (n = 6–9) and (B) tissue (n = 6–8) 5-HT levels in GF (open circles) and EX-GF (closed circles) mice. *** P < 0.001 relative to the corresponding GF value.
Fig 3.
Dynamics of luminal 5-HT concentration in the gastrointestinal tract of GF mice after colonization with SPF feces.
Male GF mice were sacrificed at 10 weeks of age for 5-HT measurements 3 (P3), 7 (P7), or 21 (P21) days after receiving SPF feces. GF mice without conventionalization were used as a control (P0). ***P < 0.001 and *P < 0.05 compared to the corresponding GF value.
Table 1.
Relative expression levels of 5-HT-related genes determined with RT-qPCR.
Fig 4.
Free, glucuronide-conjugated, and sulfate-conjugated 5-HT levels in the colonic lumens of GF and EX-GF mice.
GF and EX-GF mice were sacrificed at 10 weeks of age. Luminal free (open bars), glucuronide-conjugated (closed bars), and sulfate-conjugated (dotted bars) 5-HT levels in the colons of GF (n = 8) and EX-GF (n = 8) mice. The mean value of each form of 5-HT is expressed as the percentage of the total 5-HT (free 5-HT + conjugated 5-HT).
Table 2.
Levels of free and conjugated 5-HT in the colonic lumen of GF and EX-GF micea.