Indoleacetic acid-induced hypothermia and changes in serotonin metabolism in mice

The effects of the tryptamine metabolite, indoleacetic acid (IAA) on body temperature and serotonin (5-HT) metabolism in mice were investigated. IAA at 300 mg/kg i.p. induced significant hypothermia in mice. It caused a remarkable decrease in concentration of total tryptophan (TRP) and a considerable increase in free TRP in serum. IAA increased 5-HT, 5-hydroxyindoleacetic acid and TRP in the brain, but decreased 5-HT synthesis in the brain. The 5-HT antagonist, methysergide and the 5-HT depleter, p-chlorophenylalanine did not affect IAA-induced hypothermia.