Diazepam and Ro 15-1788 increase absence epilepsy in WAG/Rij rats chronically exposed to diazepam

The mechanisms underlying tolerance to benzodiazepines were investigated by injecting diazepam (5 mg/kg) twice daily for 23 days in WAG/Rij rats (an animal model for non-convulsive absence epilepsy). After this the rats received either the agonist, diazepam, or the antagonist, flumazenil (Ro 15-1788). EEG analyses showed that both compounds increased the amount of absence epilepsy-like phenomena. This suggests that repeated administration of diazepam moves the benzodiazepine receptor spectrum towards the inverse agonist end.