• 1 January 1983
    • journal article
    • research article
    • Vol. 265  (1) , 42-48
Abstract
The naturally occurring methylxanthines, caffeine (1, 3, 7-trimethylxanthine), theophylline (1,3-dimethylxanthine), and theobromine (3,7-dimethylxanthine), are consumed extensively in beverages and often used as therapeutic agents. 3H-Flunitrazepam (500 pM) was used to estimate the inhibitory effects of caffeine, theophylline, theobromine and 3-methylxanthine on binding to rat brain homogenates. Caffeine and theophylline showed a low affinity competitive type of inhibition in vitro, but no inhibition in vivo. Low concentrations of caffeine failed to show clear inhibitory capabilities against low concentrations of 3H-flunitrazepam. Only the toxic CNS effects of methylxanthines are apparently mediated via the benzodiazepine receptor.