L ‐theanine ameliorate depressive‐like behavior in a chronic unpredictable mild stress rat model via modulating the monoamine levels in limbic–cortical–striatal–pallidal–thalamic‐circuit related brain regions

This study aims to investigate the effects of L‐theanine (2 mg/kg) on monoamine levels in an animal model of depression. The effect ofl‐theanine on the symptoms of depression was examined through the open‐field test, sucrose preference test, and forced swim test. The monoamine neurotransmitters that involve serotonin (5‐HT), norepinephrine (NE), and dopamine (DA) were measured in the limbic–cortical–striatal–pallidal– thalamic (LCSPT)‐circuit related brain regions, including the prefrontal cortex (PFC), nucleus accumbens (NAC), striatum (ST), amygdala, and hippocampus (HIP). L‐theanine ameliorated the depressive‐like behaviors in the chronic unpredictable mild stress (CUMS) rat model. In the PFC, NAC, and H IP, L‐theanine administration significantly increased the levels of 5‐HT, NE, and DA. In the ST, the levels of 5‐HT and DA were increased after the administration of L‐theanine. However, in the HIP, only the level of DA significantly changed after the treatment of L‐theanine. Taken togethe r, these results indicated that L‐theanine has possibly antidepressant‐like effects in the CUMS rat model, which could be mediated by the monoamine neurotransmitters in the LCSPT‐circuit related brain regions.

Source: Phytotherapy Research - November 25, 2018 Category: Biochemistry Authors: Manjun Shen, Yi Yang, Ying Wu, Beibei Zhang, Haishan Wu, Lu Wang, Hui Tang, Jindong Chen Tags: RESEARCH ARTICLE Source Type: research