Facilitated neurogenesis in the developing hippocampus after intake of theanine, an amino acid in tea leaves, and object recognition memory

Cell Mol Neurobiol. 2011 Oct;31(7):1079-88. doi: 10.1007/s10571-011-9707-0. Epub 2011 May 22.

Abstract

Theanine, γ-glutamylethylamide, is one of the major amino acid components in green tea. In this study, cognitive function and the related mechanism were examined in theanine-administered young rats. Newborn rats were fed theanine through dams, which were fed water containing 0.3% theanine, and then fed water containing 0.3% theanine after weaning. Theanine level in the brain was under the detectable limit 6 weeks after the start of theanine administration. Theanine administration did not influence locomotor activity in the open-field test. However, rearing behavior was significantly increased in theanine-administered rats, suggesting that exploratory activity is increased by theanine intake. Furthermore, object recognition memory was enhanced in theanine-administered rats. The increase in exploratory activity in the open-field test seems to be associated with the enhanced object recognition memory after theanine administration. On the other hand, long-term potentiation (LTP) induction at the perforant path-granule cell synapse was not changed by theanine administration. To check hippocampal neurogenesis, BrdU was injected into rats 3 weeks after the start of theanine administration, and brain-derived neurotropic factor (BDNF) level was significantly increased at this time. Theanine intake significantly increased the number of BrdU-, Ki67-, and DCX-labeled cells in the granule cell layer 6 weeks after the start of theanine administration. This study indicates that 0.3% theanine administration facilitates neurogenesis in the developing hippocampus followed by enhanced recognition memory. Theanine intake may be of benefit to the postnatal development of hippocampal function.

MeSH terms

  • Animals
  • Animals, Newborn
  • Behavior, Animal / drug effects
  • Brain-Derived Neurotrophic Factor / metabolism
  • Cell Proliferation / drug effects
  • Female
  • Glutamates / pharmacology*
  • Hippocampus / cytology*
  • Hippocampus / drug effects
  • Hippocampus / growth & development*
  • Humans
  • Learning / drug effects
  • Male
  • Motor Activity / drug effects
  • Neurogenesis / drug effects*
  • Plant Extracts / chemistry
  • Plant Leaves / chemistry*
  • Pregnancy
  • Rats
  • Recognition, Psychology / drug effects*
  • Recognition, Psychology / physiology
  • Stem Cells / drug effects
  • Stem Cells / physiology
  • Tea / anatomy & histology
  • Tea / chemistry*

Substances

  • Brain-Derived Neurotrophic Factor
  • Glutamates
  • Plant Extracts
  • Tea
  • theanine