title: Theanine intake improves the shortened lifespan, cognitive dysfunction and behavioural depression that are induced by chronic psychosocial stress in mice.
abstract: 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.
authors.affiliation: Laboratory of Bioorganic Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan. unno@u-shizuoka-ken.ac.jp
authors.forename: Keiko
authors.initials: K
authors.lastname: Unno
authors.forename: Keisuke
authors.initials: K
authors.lastname: Fujitani
authors.forename: Nina
authors.initials: N
authors.lastname: Takamori
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Takabayashi
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Maeda
authors.forename: Hideaki
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Naoki
authors.initials: N
authors.lastname: Tanida
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Iguchi
authors.forename: Kayoko
authors.initials: K
authors.lastname: Shimoi
authors.forename: Minoru
authors.initials: M
authors.lastname: Hoshino
mesh_terms: D000818:Animals; D002908:Chronic Disease; D003072:Cognition Disorders / Q000188:drug therapy* / Q000209:etiology; D003345:Corticosterone / Q000097:blood; D003866:Depressive Disorder / Q000188:drug therapy* / Q000209:etiology; D005971:Glutamates / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D008136:Longevity / Q000187:drug effects*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D013315:Stress, Psychological / Q000150:complications*
chemical_list: D005971:Glutamates; C026166:theanine; D003345:Corticosterone