Effects of adenosine receptor agonists and antagonists on pentylenetetrazole-induced amnesia.
The effect of adenosine agents on amnesia induced by pentylenetetrazole was examined in mice. Post-training administration of pentylenetetrazole (50 and 60 mg/kg) disrupted 24-h retention of a single-trial passive avoidance task. The adenosine receptor antagonists, theophylline (2.5-25 mg/kg) and 8-phenyltheophylline (0.5-2 mg/kg), administered 30 min before and just after training at doses which did not affect retention, reduced the amnestic effect of pentylenetetrazole in a dose-dependent manner. Post-training administration of the adenosine A(1) receptor agonists, N(6)-cyclohexyladenosine (CHA, 0.1 and 0.5 mg/kg) and N(6)-phenylisopropyladenosine (R-PIA, 0.03 and 0.1 mg/kg), but not the adenosine A(2) receptor agonist, 5'-N-ethylcarboxamidoadenosine (NECA, 0.01 and 0.001 mg/kg), impaired retention. Nonamnestic doses of CHA and R-PIA potentiated the disruption induced by a lower dose of pentylenetetrazole (40 mg/kg). NECA did not induce any response in this respect. It is suggested that an adenosine A(1) receptor mechanism is involved in amnesia induced by pentylenetetrazole.
Homayoun
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H
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784, Tehran, Iran.
Khavandgar
S
S
Zarrindast
M R
MR
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000647:Amnesia / Q000139:chemically induced / Q000503:physiopathology*; D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D003292:Convulsants / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D008297:Male; D051379:Mice; D010433:Pentylenetetrazole / Q000008:administration & dosage*; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D012153:Retention, Psychology / Q000187:drug effects; D013806:Theophylline / Q000031:analogs & derivatives* / Q000494:pharmacology
D003292:Convulsants; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; C047235:N-(1-methyl-2-phenylethyl)adenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D013806:Theophylline; C028322:8-phenyltheophylline; D000241:Adenosine; D010433:Pentylenetetrazole