Effect of tryptophan on the behavior of nonstressed and stressed mice in Porsolt's swim test

Pharmacol Biochem Behav. 1990 Oct;37(2):273-6. doi: 10.1016/0091-3057(90)90333-d.


The effect of tryptophan on immobility in Porsolt's swim test was studied in male NIH Swiss mice. Preexposure to a swim or fight-stressor was included in the design. Doses of tryptophan (0, 12.5, 50, 75, 100, 125 and 200 mg/kg) were administered intraperitoneally 60 min prior to the swim test. In the nonstressed mice tryptophan had an U-shaped dose-response relationship: immobility in the water was dose-dependently shortened after doses from 0 to 100 mg/kg, whereas after 125 and 200 mg/kg tryptophan the immobility times did not differ from the values obtained after a saline injection. Preexposure to a swim- or fight-stressor did not make mice more sensitive to the effects of tryptophan. Tryptophan (0-300 mg/kg) had no effect on exploratory behavior or locomotor activity in the holeboard, suggesting that sedation was not a factor in the swim test results. The findings suggest that tryptophan has antidepressant -like properties in Porsolt's swim test.

MeSH terms

  • Animals
  • Antidepressive Agents*
  • Disease Models, Animal
  • Male
  • Mice
  • Motor Activity / drug effects*
  • Psychological Tests / methods
  • Stress, Psychological / drug therapy*
  • Swimming
  • Tryptophan / pharmacology*


  • Antidepressive Agents
  • Tryptophan