Intra-amygdaloid injection of kainic acid in rats with genetic absence epilepsy: the relationship of typical absence epilepsy and temporal lobe epilepsy.

We showed previously that genetic absence epilepsy rats from Strasbourg (GAERS) resist secondary generalization of focal limbic seizures after electrical kindling. We now investigate the effect of intra-amygdaloid injection of kainic acid, as another model of temporal lobe epilepsy, focusing on epileptogenesis, spike-and-wave discharges (SWDs), and the transition from basal to SWD states in GAERS. The EEG was recorded from the hippocampus and cortex of adult GAERS and Wistar rats before kainic acid injections into the basolateral amygdala and for 3 months thereafter.

The effect of generalized absence seizures on the progression of kindling in the rat.

The involvement of the thalamus in limbic epileptogenesis has recently drawn attention to the connectivity between the nuclei of the thalamus and limbic structures. Thalamo-limbic circuits are thought to regulate limbic seizure activity whereas thalamocortical circuits are involved in the expression and generation of spike-and-wave discharges (SWDs) in the absence epilepsy models. Genetic Absence Epilepsy Rats From Strasbourg (GAERS) and WAG/Rij (Wistar Albino Glaxo from Rijswijk) are well-defined genetic animal models of absence epilepsy.

Amygdala kindling in the WAG/Rij rat model of absence epilepsy.

Purpose: The kindling model in rats with genetic absence epilepsy is suitable for studying mechanisms involved in the propagation and generalization of seizure activity in the convulsive and nonconvulsive components of epilepsy. In the present study, we compared the amygdala kindling rate and afterdischarge characteristics of the nonepileptic Wistar control rat with a well-validated model of absence epilepsy, the WAG/Rij rat, and demonstrated the effect of amygdala kindling on spike-and-wave discharges (SWDs) in the WAG/Rij group.

Methods: Electrodes were stereotaxically implanted into the basolateral amygdala of rats for stimulation and recording and into the cortex for recording.