Interaction between methylxanthines and the benzodiazepine receptor.
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. The results suggest that only the toxic central nervous system effects of methylxanthines are mediated via the benzodiazepine receptor.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002110:Caffeine / Q000494:pharmacology*; D005445:Flunitrazepam / Q000378:metabolism; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000187:drug effects* / Q000378:metabolism; D011963:Receptors, GABA-A; D013806:Theophylline / Q000494:pharmacology*
D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D002110:Caffeine; D005445:Flunitrazepam; D013806:Theophylline