Format

Send to

Choose Destination
J Clin Biochem Nutr. 2016 Sep;59(2):93-99. Epub 2016 Jul 16.

l-Theanine protects against excess dopamine-induced neurotoxicity in the presence of astrocytes.

Author information

1
Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
2
Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan; Department of Medical Neurobiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
3
Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan; Department of Medical Neurobiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan; SAIDO Co., Fukuoka 810-0021, Japan.
4
Laboratory of Pharmacology, Kyushu Nutrition Welfare University School of Health Science, Fukuoka 803-8511, Japan.

Abstract

l-Theanine (γ-glutamylethylamide), a component of green tea, is considered to have regulatory and neuroprotective roles in the brain. The present study was designed to determine the effect of l-theanine on excess dopamine-induced neurotoxicity in both cell culture and animal experiments. The primary cultured mesencephalic neurons or co-cultures of mesencephalic neurons and striatal astrocytes were pretreated with l-theanine for 72 h, and then treated with excess dopamine for further 24 h. The cell viability of dopamine neurons and levels of glutathione were evaluated. Excess dopamine-induced neurotoxicity was significantly attenuated by 72 h preincubation with l-theanine in neuron-astrocyte co-cultures but not in neuron-rich cultures. Exposure to l-theanine increased the levels of glutathione in both astrocytes and glial conditioned medium. The glial conditioned medium from l-theanine-pretreated striatal astrocytes attenuated dopamine-induced neurotoxicity and quinoprotein formation in mesencephalic neurons. In addition, replacement of l-glutamate with l-theanine in an in vitro cell-free glutathione-synthesis system produced glutathione-like thiol compounds. Furthermore, l-theanine administration (4 mg/kg, p.o.) for 14 days significantly increased glutathione levels in the striatum of mice. The results suggest that l-theanine provides neuroprotection against oxidative stress-induced neuronal damage by humoral molecules released from astrocytes, probably including glutathione.

KEYWORDS:

astrocyte; dopamine; glutathione; l-theanine; neuroprotection

Supplemental Content

Full text links

Icon for J-STAGE, Japan Science and Technology Information Aggregator, Electronic Icon for PubMed Central
Loading ...
Support Center