L-theanine Administration Results in Neuroprotection and Prevents Glutamate Receptor Agonist-Mediated Injury in the Rat Model of Cerebral Ischemia-Reperfusion

Phytother Res. 2013 Sep;27(9):1282-7. doi: 10.1002/ptr.4868. Epub 2012 Oct 24.

Abstract

While the neuroprotective effect of green tea (Camellia sinensis) might be explained by the presence of amino acid L-theanine in the tea leaves, it is not known whether postischemic administration of L-theanine could also provide neuroprotection. In the present study, we investigated the neuroprotective effect of L-theanine (1 and 4 mg/kg) administered at 3, 12, and 24 h after reperfusion in the rat model of stroke. We also studied the effect of L-theanine on brain injury caused by exogenous administration of N-methyl-D-aspartate and α-amino-3-hydroxy-5-methyl-isoxazole-4-propionate/kainate receptor agonists during reperfusion. Rats were subjected to 30-min middle cerebral artery occlusion followed by 48-h reperfusion. Neurological deficit and infarct size were determined at the end of reperfusion. At 3 and 12 h, but not at 24 h of reperfusion, L-theanine substantially reduced the size of brain infarct. Neurological status was improved when L-theanine was administered 3, 12, and 24 h after reperfusion. Repeated intrastriatal injections of L-theanine at a total dose of 800 µg/kg during reperfusion prevented brain injury caused by glutamate receptor agonists. In conclusion, L-theanine at reperfusion exerts neuroprotective effect in the in vivo rat model of stroke. Local treatment with L-theanine at reperfusion prevents glutamate receptor agonist-mediated brain injury.

Keywords: L-theanine; brain ischemia; neuroprotection; rat; reperfusion.

MeSH terms

  • Animals
  • Brain / drug effects
  • Brain / pathology
  • Camellia sinensis / chemistry
  • Excitatory Amino Acid Agonists / adverse effects*
  • Glutamates / administration & dosage
  • Glutamates / pharmacology*
  • Infarction, Middle Cerebral Artery / drug therapy*
  • Male
  • N-Methylaspartate / adverse effects
  • Neuroprotective Agents / administration & dosage
  • Neuroprotective Agents / pharmacology*
  • Rats
  • Rats, Wistar
  • Receptors, Glutamate / metabolism
  • Reperfusion Injury / drug therapy*
  • Reperfusion Injury / prevention & control
  • Tea / chemistry

Substances

  • Excitatory Amino Acid Agonists
  • Glutamates
  • Neuroprotective Agents
  • Receptors, Glutamate
  • Tea
  • N-Methylaspartate
  • theanine