title: Pyrazolo [3,4-d] pyrimidines, a new class of adenosine antagonists.
abstract: A variety of nitrogen heterocycles structurally related to caffeine and theophylline have been tested for activity as adenosine receptor antagonists. Preliminary screening, utilizing displacement of [3H]N6-phenylisopropyladenosine binding to rat brain membrane A1-adenosine receptors, identified several pyrazolo[3,4-d]pyrimidines with potential antagonist activity. These were then tested for their ability to antagonize the adenosine-stimulated adenylate cyclase system of guinea-pig brain slices. One of these, 4,6-bis-alpha-carbamoylethylthio-1-phenylpyrazolo[3,4-d]pyrimidine (DJB-KK), was over an order of magnitude more potent than theophylline in blocking adenosine-stimulated increases in cyclic AMP levels.
mesh_terms: D000241:Adenosine / Q000037:antagonists & inhibitors*; D000818:Animals; D001921:Brain / Q000648:ultrastructure; D000242:Cyclic AMP / Q000037:antagonists & inhibitors; D006168:Guinea Pigs; D011720:Pyrazoles / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology
chemical_list: D011720:Pyrazoles; D011743:Pyrimidines; D013806:Theophylline; D000242:Cyclic AMP; D000241:Adenosine