Involvement of GABA_A Receptors in the Neuroprotective Effect of Theanine on Focal Cerebral Ischemia in Mice

Abstract

We investigated the involvement of γ-aminobutyric acid_A (GABA_A) receptors in the neuroprotective effect of γ-glutamylethylamide (theanine), a component of Japanese green tea, following a 4-h middle cerebral artery (MCA) occlusion in mice. Theanine (1 mg/kg) reduced the size of the cerebral infarct and alterations of NeuN, GFAP, and Iba 1 expression levels at 24 h after MCA occlusion. This neuroprotective effect of theanine was prevented by bicuculline (GABA_A-receptor antagonist, 10 mg/kg) but not 3-mercaptopropionic acid (glutamate decarboxylase inhibitor). These results suggest that the neuroprotective effect of theanine is mediated, at least in part, by GABA_A receptors.