Abstract
Both theanine (L-N-ethylglutamine) and L-glutamine were found to have a weak depressing effect on the spontaneous activity of mice and to decrease the activity enhanced by the administration of caffeine. These amides, however, did not depress the activity induced by pipradrol or methamphetamine and the hyperactivity produced with hexobarbital. Sodium glutamate did not show any depression on the activity increased by caffeine in mice, while γ-aminobutyric acid depressed it to a lesser extent than theanine. Studies on the effects of theanine and L-glutamine at various periods after administration of these chemicals suggested that the depression mechanisms of these amides might be similar on the caffeine-increased spontaneous activity of mice.
