Amygdala kindling in the WAG/Rij rat model of absence epilepsy.
OBJECTIVE
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. After a recovery period, the animals were stimulated at their afterdischarge thresholds. EEG was recorded to analyze SWDs and afterdischarge durations. The seizure severity was evaluated by using Racine's 5-stage scale.


RESULTS
All nonepileptic control and four of seven WAG/Rij animals reached a stage 5 seizure state, whereas three animals failed to reach stage 3, 4, or 5 and stayed at stage 2 after application of 30 stimulations. Interestingly, WAG/Rij rats, resistant to kindling, demonstrated a significantly longer duration of SWDs on the first day of the experiment before kindling stimulation than did the kindled WAG/Rij animals. Additionally, the cumulative total duration and the number of SWDs after the kindling stimulation were statistically increased compared with SWDs before kindling stimulation.


CONCLUSIONS
The results of our study demonstrate that the progress of amygdala kindling is changed in rats with genetic absence epilepsy, perhaps as a consequence of the hundreds of daily SWDs.
Aker
Rezzan Gülhan
RG
Department of Pharmacology and Clinical Pharmacology, School of Medicine, Marmara University, Istanbul.
Yananli
Hasan Raci
HR
Gurbanova
Ayten Azizova
AA
Ozkaynakçi
Aydan Ergün
AE
Ateş
Nurbay
N
van Luijtelaar
Gilles
G
Onat
Filiz Yilmaz
FY
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D004195:Disease Models, Animal; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods / Q000706:statistics & numerical data*; D004832:Epilepsy, Absence / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D007696:Kindling, Neurologic / Q000502:physiology*; D008032:Limbic System / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D012720:Severity of Illness Index; D013238:Stereotaxic Techniques