Implementing a bioassay to screen molecules for antiepileptogenic activity: chronic pilocarpine versus subdudral haematoma models

BACKGROUND There is a need to discover novel chemical compounds that will inhibit the pathological process of epileptogenesis (i.e. agents that will prevent the long-term formation of an active seizure focus following a brain insult). The goal of this paper is to identify a bioassay of value in drug design when screening new chemical entities as putative antiepileptogenic agents. METHODS We focused on two models: the pilocarpine chronic seizure model of spontaneous recurrent seizures (SRSs) and a chronic subdural haematoma model of SRSs. Both models were evaluated using more than 20 Sprague-Dawley rats for each model. RESULTS In the pilocarpine-induced model of SRSs, 80% of animals went on to develop SRSs when the dose of pilocarpine was 380 mg/kg i.p. In 50 animals that developed SRSs, the average number of seizures per 15 days of observation was 3.8 seizures with a range of 2-23 seizures per 15-day period. The chronic subdural model was inefficient in producing SRSs. CONCLUSIONS A pilocarpine-induced SRS model of epilepsy affords a reliable model of epileptogenesis suitable for evaluating new chemical entities as putative antiepileptogenics.