The effect of tryptophan administration on ileum contractility and oxidant status in mice

Amino Acids. 2007;32(3):453-8. doi: 10.1007/s00726-006-0339-5. Epub 2006 May 26.


L-tryptophan (TRP) is the precursor amino acid for the synthesis of serotonin (5-HT). 5-HT is effective both on the food intake and gastrointestinal system contractility. The aim of this study was to search the effects of systemic TRP treatment on 5-HT levels of ileum and searching the effect of ileal contractility and oxidant status. Swiss-albino mice were divided into two groups: 1. Control, 2. TRP-treated (100 mg/kg/24 h, i.p., for 7 days). Body weights were recorded at the beginning and at the end of experiments. Acetylcholine-induced contractile responses in the isolated ileum were recorded on polygraph. Ileal tissue malondialdehyde and glutathione levels determined by spectrophotometric and ileal tissue 5-HT levels were measured by immunohistochemical methods. TRP treatment decreased body weight and increased ileal contractile response. In the TRP-treated group, ileum malondialdehyde levels increased and glutathione levels decreased. Immunohistochemical detection showed that ileal 5-HT levels were increased by TRP treatment. There is a relationship between increased oxidative stress and increased contractility in the ileal tissue of the TRP-treated animals. These effects may be related to increased ileal 5-HT synthesis.

Publication types

  • Comparative Study

MeSH terms

  • Acetylcholine / pharmacology
  • Animals
  • Antidepressive Agents, Second-Generation / administration & dosage*
  • Cholinergic Agents / pharmacology
  • Eating / drug effects
  • Glutathione / metabolism
  • Ileum / metabolism*
  • Male
  • Malondialdehyde / metabolism
  • Mice
  • Muscle Contraction / drug effects*
  • Organ Culture Techniques
  • Oxidative Stress / drug effects*
  • Serotonin / biosynthesis
  • Tryptophan / administration & dosage*


  • Antidepressive Agents, Second-Generation
  • Cholinergic Agents
  • Serotonin
  • Malondialdehyde
  • Tryptophan
  • Glutathione
  • Acetylcholine