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

Mika Takeshima, Ikuko Miyazaki, Shinki Murakami, Taizo Kita, Masato Asanuma

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


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 languageEnglish
Pages (from-to)93-99
Number of pages7
Journaljournal of clinical biochemistry and nutrition
Issue number2
Publication statusPublished - Sep 2016


  • Astrocyte
  • Dopamine
  • Glutathione
  • L-theanine
  • Neuroprotection

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Clinical Biochemistry


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