THE GENETICALLY EPILEPSY-PRONE RAT (GEPR)

Two independently inbred strains of genetically epilepsy-prone rats (GEPRs) have been developed. GEPR-3s and GEPR-9s have moderate and severe degrees of seizure predisposition as well as expression, respectively. Seizure predisposition is a fundamental distinction between the normal and epileptic brain. Seizure predisposition in GEPRs and in humans with epilepsy includes spontaneous seizures and exaggerated seizure responsiveness and/or abnormally low thresholds to stimuli which also cause seizures in non-epileptic subjects. Activation of brainstem seizure circuitry by auditory input via the inferior colliculus causes electrographic and behavioral responses in GEPR-9s which replicates human generalized tonic/clonic seizures, Activation of brainstem seizure circuitry by input from forebrain seizure circuitry in GEPRs provides a newly discovered model of complex partial seizures with secondary generalization to tonic/clonic seizures, Thus seizure predisposition in GEPRs offers a unique opportunity to study the human epilepsies that is not offered in studies of normal brain exposed to convulsant stimuli.