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 mesence- phalic 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 com- pounds. 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 neuroprotec- tion against oxidative stress-induced neuronal damage by humoral molecules released from astrocytes, probably including glutathione.
Original language | English |
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Pages (from-to) | 93-99 |
Number of pages | 7 |
Journal | journal of clinical biochemistry and nutrition |
Volume | 59 |
Issue number | 2 |
DOIs | |
Publication status | Published - Sep 2016 |
Keywords
- Astrocyte
- Dopamine
- Glutathione
- L-theanine
- Neuroprotection
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Nutrition and Dietetics
- Clinical Biochemistry