Effect of L-theanine on cerebellar granule cell migration related to cognitive disorders

Cerebellar granule cell migration plays a crucial role in cerebellum development, and any abnormalities in CGC migration can lead to significant neurological disorders such as anxiety, a common psychological disorder that impacts a person's emotional, physical, and social health. L-theanine, an amino acid found in green tea, demonstrates neuroprotective properties and regulates the release of neurotransmitters by stimulating CGC migration. This study investigated the impact of L-theanine on CGC migration related to cognitive disorders.

ddY male mice treated with a single oral dose of L-theanine at varying concentrations (10 mg/kg) were assessed for anxiety, learning, and memory using the maze test and the Morris Water Maze test, where the average completion time and escape time of the mice were considered indicators of cognitive performance. CGC microexplants were isolated from newly born C57BL/N6 mice and treated with a series of increasing concentrations of L-theanine. The migration distance of the CGC under the different L-theanine concentrations was assessed after 24, 48, and 72 h post-treatment using phase-contrast microscopy and image analysis software.

Mice's anxiety symptoms improved based on their performance on the maze test after treatment with L-theanine at 5 mg/ml. However, L-theanine at 0.05 mg/ml enhanced learning and memory abilities. Compared to other concentrations, L-theanine at 1 µM yielded the longest migration distance for CGC in vitro. Therefore, L-Theanine may serve as a potential therapeutic agent in supporting cerebellar development and enhancing cognitive skills. Further investigation is required to fully elucidate the molecular mechanisms and therapeutic potential of L-theanine in neurodevelopmental disorders.