Learning Objective 1: discuss the hypothesis of the study: Does the green tea compound, L-theanine, have anxiolytic effects in the laboratory rat?
Learning Objective 2: describe the findings of the study that L-theanine combined with midazolam significantly decreased anxiety, motor movements, and locomotion.
Methods: A five group prospective study using an experimental between groups design was used. Fifty-five rats were divided into five groups: control; L-theanine; midazolam (positive control); flumazenil plus L-theanine; and midazolam plus L-theanine. The behavioral component of anxiety was evaluated using the elevated plus maze. Data analysis was performed using a two-tailed Multivariate Analysis of Variance (MANOVA) and Sheffe post-hoc test.
Results: Data suggest that L-theanine does not produce anxiolysis by modulation of the GABAA receptor; however, in combination with midazolam, a synergistic or additive effect was demonstrated by decreased anxiety, motor movements and locomotion.
Conclusion: L-theanine may affect anxiety and movement. Future experiments should explore anxiolytic and motor effects of L-theanine using other balance and locomotion instruments such as the rotorod. Additional studies might include investigating the effects of L-theanine at glutamatergic receptors and at the neuromuscular junction. As evidenced by this research, the use of herbals such as L-theanine (a green tea compound) may have important interactions with other medications (e.g., midazolam) and may result in significant adverse effects. These data may provide direction for further studies examining L-theanine and its effects on anxiety and motor activity, a concern for healthcare providers whose patients are consuming green tea.