A Comprehensive Behavioral Evaluation in the Lithium-pilocarpine Model in Rats: Effects of Carisbamate Administration During Status Epilepticus

Purpose: Administration of carisbamate during status epilepticus (SE) prevents the occurrence of motor seizures in the lithium-pilocarpine model and leads in a subpopulation of rats to spike-and-wave discharges characteristic of absence epilepsy. Widespread neuroprotection accompanied this change in seizure expression. To assess whether these carisbamate-induced changes affected comorbidity, we used a large battery of behavioral tests in rats that had developed temporal lobe or absence-like seizures.

Methods: Lithium-pilocarpine or saline was administered to 60 adult rats. Carisbamate (90 mg/kg) or diazepam and saline was given 1 h after SE onset, and repeated 8 h later and twice daily over 6 more days. Rats were video-monitored for 2 months. Subsequently, locomotor activity, anxiety, and various types of memory were assessed.

Key Findings: In rats with motor seizures, treated or not with carisbamate, all features of behavior were impaired compared to controls. Rats exhibiting absence-like seizures after carisbamate treatment behaved as controls in all paradigms tested along with widespread neuroprotection.

Significance: Carisbamate treatment leading to absence-like instead of temporal lobe seizures impressively prevented behavioral comorbidities reported by patients with epilepsy as the most disabling.