title: Antagonism of the behavioral effects of L-phenylisopropyladenosine (L-PIA) by caffeine and its metabolites.
abstract: Three male Sprague-Dawley strain rats were trained to respond under a multi-component time out 5 min variable ratio 15 (VR15) schedule of food reinforcement. Cumulative, within session dose-effect curves were determined for L-PIA alone and after methylxanthine pretreatment. L-PIA alone produced dose related decreases on VR15 responding at doses between 0.032 and 0.178 mg/kg. Significant antagonism of L-PIA was demonstrated from pretreatment with caffeine, theophylline, theobromine, paraxanthine, 3-methylxanthine, and 7-methylxanthine. No antagonism of L-PIA was observed following pretreatment with 1-methylxanthine. Consistent with the adenosine receptor blockade hypothesis, caffeine also antagonized the effects of 5'-N-ethylcarboxamide adenosine (NECA) on VR15 responding.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D002110:Caffeine / Q000378:metabolism / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects*; D008297:Male; D010660:Phenylisopropyladenosine / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains; D013806:Theophylline / Q000494:pharmacology; D014970:Xanthines / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D014970:Xanthines; C008514:methylxanthine; D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); D002110:Caffeine; D013806:Theophylline; D000241:Adenosine