title: Preventive effect of theanine intake on stress-induced impairments of hippocamapal long-term potentiation and recognition memory.
abstract: Theanine, γ-glutamylethylamide, is one of the major amino acid components in green tea. On the basis of the preventive effect of theanine intake after birth on mild stress-induced attenuation of hippocamapal CA1 long-term potentiation (LTP), the present study evaluated the effect of theanine intake after weaning on stress-induced impairments of LTP and recognition memory. Young rats were fed water containing 0.3% theanine for 3 weeks after weaning and subjected to water immersion stress for 30min, which was more severe than tail suspension stress for 30s used previously. Serum corticosterone levels were lower in theanine-administered rats than in the control rats even after exposure to stress. CA1 LTP induced by a 100-Hz tetanus for 1s was inhibited in the presence of 2-amino-5-phosphonovalerate (APV), an N-methyl-d-aspartate (NMDA) receptor antagonist, in hippocampal slices from the control rats and was attenuated by water immersion stress. In contrast, CA1 LTP was not significantly inhibited in the presence of APV in hippocampal slices from theanine-administered rats and was not attenuated by the stress. Furthermore, object recognition memory was impaired in the control rats, but not in theanine-administered rats. The present study indicates the preventive effect of theanine intake after weaning on stress-induced impairments of hippocampal LTP and recognition memory. It is likely that the modification of corticosterone secretion after theanine intake is involved in the preventive effect.
authors: Graduate School of Pharmaceutical Sciences, University of Shizuoka, Global COE, Japan.
authors: Haruna
authors: H
authors: Tamano
authors: Kotaro
authors: K
authors: Fukura
authors: Miki
authors: M
authors: Suzuki
authors: Kazuhiro
authors: K
authors: Sakamoto
authors: Hidehiko
authors: H
authors: Yokogoshi
authors: Atsushi
authors: A
authors: Takeda
mesh_terms: D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005971:Glutamates / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D021641:Recognition, Psychology / Q000187:drug effects* / Q000502:physiology; D013312:Stress, Physiological / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects; D013662:Tea / Q000737:chemistry
chemical_list: D005971:Glutamates; D010936:Plant Extracts; D016194:Receptors, N-Methyl-D-Aspartate; D013662:Tea; D015763:2-Amino-5-phosphonovalerate; C026166:theanine