Protective effect of gamma-glutamylethylamide (theanine) on ischemic delayed neuronal death in gerbils

We examined the protective effect of gamma-glutamylethylamide (theanine) on ischemic delayed neuronal death in field CA1 of the gerbil hippocampus. On e microliter of theanine from each three concentrations (50, 125 and 500 mu M) was administered through the lateral ventricle 30 min before ischemia. Transient forebrain ischemia was induced by bilateral occlusion of the comm on carotid arteries for 3 min under careful control of brain temperature at approximately 37 degrees C. Seven days after ischemia, the number of intac t CA1 neurons in the hippocampus was assessed. Ischemia-induced neuronal de ath in hippocampal CA1 region was significantly prevented in a dose-depende nt manner in the theanine-pretreated groups. These findings indicate that t heanine might be useful clinically for preventing ischemic neuronal damage. (C) 2000 Published by Elsevier Science Ireland Ltd.