Anxiolytic effects of L-theanine--a component of green tea--when combined with midazolam, in the male Sprague-Dawley rat

AANA J. 2009 Dec;77(6):445-9.

Abstract

The purpose of the study was to investigate the anxiolytic effects of L-theanine and its potential interaction with the GABAA receptor in Sprague-Dawley rats. L-theanine is a major component of green tea, which has traditionally been used as an herbal remedy in the treatment of many medical conditions, including anxiety. Herbals and supplements and their potential interactions perioperatively are a concern to anesthetists. Fifty-five rats were divided into 5 groups: control (saline); L-theanine (positive control); flumazenil (a known benzodiazepine receptor antagonist) and L-theanine; and midazolam and L-theanine. The behavioral component of anxiety was evaluated using the elevated plus-maze and calculated by the time spent in the open arm of the maze divided by total time in the maze. Data were analyzed using a 2-tailed multivariate analysis of variance and Sheffé posthoc test. The 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 and both fine and basic motor movements. These data may provide direction for further studies examining L-theanine and its effects on anxiety and motor activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Anxiety Agents / pharmacology*
  • Anxiety / drug therapy*
  • Camellia sinensis / chemistry*
  • Drug Synergism*
  • Glutamates / pharmacology*
  • Male
  • Maze Learning / drug effects
  • Midazolam / pharmacology*
  • Multivariate Analysis
  • Phytotherapy*
  • Plant Extracts / pharmacology*
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, GABA-A / drug effects

Substances

  • Anti-Anxiety Agents
  • Glutamates
  • Plant Extracts
  • Receptors, GABA-A
  • theanine
  • Midazolam