Prevention of cysteamine-induced myoclonus blocks the long-term inhibition of kindled seizures.

In kindled rats, the administration of cysteamine (CSH, 200 mg/kg, i.p.) 4 h prior to a kindled seizure leads to long-term (up to 10 days) inhibition of kindled seizures. CSH (200 mg/kg, i.p.) also induces myoclonic seizures in kindled rats. We suggest that the long-term inhibition of kindled seizures might be the result of the myoclonus, not the somatostatin depletion as previously suggested. Prior administration of the short-acting benzodiazepine midazolam (5 mg/kg, i.p.) eliminated the CSH-induced myoclonus and prevented the long-term inhibition of kindled seizures. These results suggest that the CSH-induced long-term inhibition of kindled seizures is the result of an interaction between the myoclonic seizure and a subsequent kindled seizure.