Effects of caffeine and theophylline on adenosine and benzodiazepine receptors in human brain.
The binding of various adenosine receptor ligands and of [3H]diazepam, as well as their inhibition of methylxanthines, have been studied in human brain cerebral cortex membranes. Caffeine and theophylline competitively inhibit binding of [3H]cyclohexyladenosine, [3H]diethylphenylxanthine, [3H]phenylisopropyladenosine and [3H]diazepam. Both caffeine and theophylline are more potent as inhibitors of adenosine receptor ligand binding compared to [3H]diazepam binding. Theophylline was more potent than caffeine in its ability to compete with adenosine receptor ligand binding while the reverse was true for [3H]diazepam binding. The meaning of these results for the mode of action of methylxantine is discussed.
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002110:Caffeine / Q000494:pharmacology*; D003975:Diazepam / Q000378:metabolism; D006801:Humans; D010660:Phenylisopropyladenosine / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000187:drug effects* / Q000378:metabolism; D011955:Receptors, Drug / Q000187:drug effects* / Q000378:metabolism; D011963:Receptors, GABA-A; D011983:Receptors, Purinergic; D013806:Theophylline / Q000494:pharmacology*; D014970:Xanthines / Q000378:metabolism
D011956:Receptors, Cell Surface; D011955:Receptors, Drug; D011963:Receptors, GABA-A; D011983:Receptors, Purinergic; D014970:Xanthines; D010660:Phenylisopropyladenosine; C027512:1,3-diethyl-8-phenylxanthine; C027513:N(6)-cyclohexyladenosine; D002110:Caffeine; D013806:Theophylline; D000241:Adenosine; D003975:Diazepam