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, 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. (C) 2001 Published by Elsevier Science B.V.