THE WAG RIJ RAT MODEL FOR NONCONVULSIVE ABSENCE EPILEPSY - INVOLVEMENT OF NONNMDA RECEPTORS/

The involvement of AMPA and kainate receptors in nonconvulsive epileps y was studied by intracerebroventricular injections of AMPA, GDEE, kai nic acid and kynurenic acid in WAG/Rij rats. The WAG/Rij rat strain is recognized as an animal model for human absence epilepsy. EEG registr ations showed that AMPA (0.1 pmol/5 mu l; 1 pmol/5 mu l; 10 pmol/5 mu l) dose-dependently increased the nonconvulsive absence epilepsy while GDEE (0.2 mu mol/5 mu l; 1 mu mol/5 mu l; 5 umol/5 mu l) caused a dos e-dependent decrease. All effects of GDEE could be blocked by an inact ive AMPA dosage. Kainic acid (0.01 nmol/5 mu l; 0.1 nmol/5 mu l; 0.15 nmol/5 mu l) had no effects on the nonconvulsive epilepsy but induced convulsions in the two highest dosages. Kynurenic acid (50 nmol/5 mu l ; 100 nmol/5 mu l; 500 nmol/5 mu l) decreased dose-dependently the inc idence of nonconvulsive epilepsy. The effect of kynurenic acid could b e blocked by a nonconvulsive dosage of kainic acid. These results show that the AMPA and kainate receptor appear to be involved in nonconvul sive epilepsy. Furthermore, blockage of these two receptor subtypes le d to an antiepileptic effect without inducing behavioural alterations. Therefore, selective AMPA and kainate receptor antagonists might be p otent antiepileptics.