title: Effects of adenosine receptor agonists and antagonists on acquisition of passive avoidance learning.
abstract: A series of experiments examined the effect of the adenosine receptor agonists N(6)-cyclohexyladenosine (CHA), N(6)-phenylisopropyladenosine (R-PIA) and 5'-N-ethylcarboxamidoadenosine (NECA); the adenosine receptor antagonists theophylline, caffeine and 8-phenyltheophylline (8-PT), and the adenosine uptake inhibitor dipyridamole on acquisition of a single trial passive avoidance learning by mice. The adenosine receptor agonists CHA (0.05, 0.1, 0.2 and 0.4 mg/kg) and R-PIA (0.00625, 0.125, 0.25 and 0.5 mg/kg) administered 1 h before the training session decreased retention dose dependently while the other adenosine receptor agonist NECA (0.0025, 0.005 and 0.01 mg/kg) had no effect. The response induced by the adenosine receptor agonists CHA and R-PIA was attenuated by the pretreatment of animals with low doses of the adenosine receptor antagonists 8-PT (2.0 mg/kg) and theophylline (25 mg/kg) but not with higher doses of the antagonists. The higher doses of the antagonists decreased the passive avoidance. Dipyridamole (7.5, 15, 30, 60 and 120 mg/kg) showed no significant effect. It is concluded that adenosine A1 receptor activation decreases the acquisition of a passive avoidance response.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Teheran, Iran.
authors.forename: M R
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: B
authors.initials: B
authors.lastname: Shafaghi
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology; D004176:Dipyridamole / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D007274:Injections, Intraperitoneal; D008297:Male; D051379:Mice; D010660:Phenylisopropyladenosine / Q000494:pharmacology*; D058915:Purinergic P1 Receptor Antagonists; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D058915:Purinergic P1 Receptor Antagonists; D014665:Vasodilator Agents; D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D002110:Caffeine; D004176:Dipyridamole; D013806:Theophylline; C028322:8-phenyltheophylline; D000241:Adenosine