Genetic Absence Epilepsy in Rats from Strasbourg (GAERS)

In Genetic Absence Epilepsy Rats from Strasbourg (GAERS), 100% of the animals present recurrent generalized non-convulsive seizures characterized by bilateral and synchronous spike-and-wave discharges (SWD) accompanied with behavioural arrest, staring and sometimes twitching of the vibrissae. Spontaneous SWD (7-11 cps) start and end abruptly on a normal background EEG at a mean frequency of 1.5 per min. Drugs effective against absence seizures in humans suppress the SWD dose-dependently, whereas drugs specific for convulsive or focal seizures are ineffective. Depth EEG recordings and lesion experiments show that SWD in GAERS depend on cortical and thalamic structures with a possible rhythmic triggering by the lateral thalamus; GABAA and GABAB receptors seem to play a critical role. SWD are genetically determined with an autosomal dominant inheritance. The variable expression of SWD in offspring from GAERS and control reciprocal crosses may be due to the existence of multiple genes.