A1 adenosinergic modulation alters the duration of maximal dentate activation.

The role of adenosine systems in the initiation and termination of seizures was examined using a unique marker for limbic seizures--maximal dentate activation (MDA). At 10 mg/kg 2-chloroadenosine shortened the duration of MDA, a measure of seizure terminating processes. The selective A1 agonist, cyclopentyladenosine, at 3 mg/kg, blocked the increase in duration of MDA, while the A1 antagonist, 1,3-dipropyl-8-cyclopentylxanthine (0.05 mg/kg) had the opposite effect. None of the compounds tested altered the time to onset of MDA, a measure of processes that initiate seizures. Therefore, modulation of A1 adenosine systems appears to alter seizure termination much more than seizure initiation.