Theanine intake improves the shortened lifespan, cognitive dysfunction and behavioural depression that are induced by chronic psychosocial stress in mice

Free Radic Res. 2011 Aug;45(8):966-74. doi: 10.3109/10715762.2011.566869. Epub 2011 Mar 22.


To evaluate the psychosocial effect on lifespan and cognitive function, this study investigated the effect of confrontational housing on mice because conflict among male mice is a psychosocial stress. In addition, it investigated the anti-stress effect of theanine (γ-glutamylethylamide), an amino acid in tea. Mice were housed under confrontation. That is, two male mice were separately housed in the same cage with a partition for establishing the territorial imperative in each mouse. Then, the partition was removed and mice were co-housed confrontationally (confront-housing) using a model mouse of accelerated-senescence (SAMP10) that exhibited cerebral atrophy and cognitive dysfunction with ageing. It was found that mice began to die earlier under confront-housing than group-housed control mice. Additionally, it was found that cerebral atrophy, learning impairment and behavioural depression were higher in mice under the stressed condition of confront-housing than age-matched mice under group-housing. Furthermore, the level of oxidative damage in cerebral DNA was higher in mice housed confrontationally than group-housed control mice. On the other hand, the consumption of purified theanine (20 μg/ml, 5-6 mg/kg) suppressed the shortened lifespan, cerebral atrophy, learning impairment, behavioural depression and oxidative damage in cerebral DNA. These results suggest that psychosocial stress accelerates age-related alterations such as oxidative damage, lifespan, cognitive dysfunction and behavioural depression. The intake of theanine might be a potential candidate for suppression of disadvantage under psychosocial stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chronic Disease
  • Cognition Disorders / drug therapy*
  • Cognition Disorders / etiology
  • Corticosterone / blood
  • Depressive Disorder / drug therapy*
  • Depressive Disorder / etiology
  • Glutamates / administration & dosage
  • Glutamates / pharmacology*
  • Glutamates / therapeutic use*
  • Longevity / drug effects*
  • Male
  • Mice
  • Mice, Inbred Strains
  • Stress, Psychological / complications*


  • Glutamates
  • theanine
  • Corticosterone