Chronic reduction in dietary tryptophan leads to changes in the emotional response to stress in mice

Shusaku Uchida, Aya Kitamoto, Hisahiro Umeeda, Nobutoshi Nakagawa, Shoichi Masushige, Satoshi Kida

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


Acute depletion of brain tryptophan (TRP) levels in humans has been used as a biochemical model of depression. In this study, we examined the effects of consumption of a diet low in TRP on emotional behavior in mice. Specifically, we assessed various parameters of emotional behavior in mice fed a TRP-limited diet for at least 1 mo. TRP-limited mice showed increased defensive, but not offensive, aggression in the resident-intruder test. In the social dominance tube test, these mice showed enhanced social dominance. Since defensive aggression is thought to be a reflection of not only aggression but also fear, these changes in the social behavior of TRP-limited mice are thought to reflect changes in their emotional status. TRP-limited mice also showed increased locomotor activity and mobility in the open field and forced swim tests, respectively, suggesting that their stress/emotional responsiveness was enhanced. Importantly, these mice displayed normal levels of anxiety and motor performance as determined by the elevated zero maze and open field tests, and the rotarod test, respectively, suggesting that their hyperactivity was not due to a reduction in anxiety levels or to enhancement of their motor performance. Thus, dietary TRP restriction appears to result in alterations in the emotional response to stress, in mice.

Original languageEnglish
Pages (from-to)175-181
Number of pages7
JournalJournal of nutritional science and vitaminology
Issue number3
Publication statusPublished - 2005 Jun
Externally publishedYes


  • Aggression
  • Dietary tryptophan limitation
  • Emotional response
  • Locomotor activity
  • Mouse behavior

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


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