A Study On The Protective Effects Of Theanine On The Induced Brain Damnification By Ischemia-reperfusion In Rabbit

Theanine, r-glutamylethylamide, is one of the characteristic components of amino acids in the tea. Theanine was reported to be biologically active in reducing systemic blood pressure , producing a relaxation effect, and suppressing the stimulatory action of caffeine. It has not been reported that theanine has a neuroprotective effect. We then investigated the neuroprotective effect of theanine in the model of induced brain damnification by ischemia-reperfusion in a step-through test ,meanwhile histopathological changes,brain water content and neuron-specific enolase(NSE) were evaluated in different groups. The studies were done with the following four experimental groups: 1) sham-operated animals group administered parting blood vessel without ligating: 2)ischemia group administered ischemia and reperfusion:3)theanine-pretreated group administered theanine 4 hours before the ischemia event and 4)theanine-treated group administered theanine just before reperfusion. Blood was gathered from jugular vein respectively before treatment,and at 30min, 1hour ,2hour after reperfusion in order to measurate NSE before histopathological changes and brain water content were tested. In the theanine-pretreated and theanine-treated groups , all of the above changes were improved remarkably. It is the conclusion that theanine has a fine effect on the induced brain damnification by ischemia-reperfusion and the theanine-pretreated is more effective than the theanine-treated. One of the mechanisms of theanine responsible for its neuroprotective effect is associated with glutamate receptors as an antagonist because theanine has been found to have a binding capacity to the receptors of glutamic. However, it has been shown that the actions of theanine are very mild compared with those of glutamic acid. Therefore the mechanism of neuroprotective effect of theanine is related not only to the glutamate receptors but also to other mechanisms such as the glutamate transporter, further studies are needed and warranted. This will be a newly therapeutic way for the patients with stroke or having tendence toward stroke.