The relationship between age-related development of spike-and-wave discharges and the resistance to amygdaloid kindling in rats with genetic absence epilepsy

Genetic Absence Epilepsy Rats from Strasbourg (GAERS) are resistant to amygdaloid kindling. Since in GAERS the characteristics of spike-and-wave discharges (SWDs) change with age, we have studied the relation between SWD maturation and the development of kindling resistance. Non-epileptic Wistar rats and GAERS were stimulated in basolateral amygdala with 400 μA at 20 min intervals until they reached stage 5 seizures or for a maximum of 36 stimulations. All of the Wistar rats, the postnatal (PN) day 20 GAERS and the (kindling-prone) subgroups of GAERS at PN30 and PN60 reached stage 5 seizures; at PN20, PN30 and PN60 kindling rates were significantly slower in GAERS compared to Wistar rats. At PN30 and PN60, 41% and 69% of GAERS, respectively, showed no stage 3, 4 or 5 seizures after 36 stimulations (kindling-resistant subgroups). The SWD maturation involves changes in spectral patterns and correlate with age-related increases in kindling resistance in GAERS.