Proconvulsant effects of theophylline on hippocampal afterdischarges

We tested the effects of the adenosine antagonist, theophylline, on electrically induced afterdischarges in the hippocampus of rats. Theophylline did not significantly alter the threshold for afterdischarge initiation or the duration of the initial afterdischarge. However, theophylline greatly prolonged the duration of secondary afterdischarges, and permitted generalization to motor seizures. Because theophylline antagonizes adenosine, and the hippocampus is a region rich in adenosine binding sites, we interpret these results to mean that endogenous adenosine has little action on focal seizure initiation, but a strong action to suppress secondary seizures and to inhibit seizure generalization.