Consequences of Lithium-Pilocarpine Status Epilepticus in Immature GAERS.
Abstract number :
3.005
Submission category :
Year :
2001
Submission ID :
185
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
C. Dube, PhD, INSERM U 398, Strasbourg, France; E. Koning, INSERM U 398, Strasbourg, France; A. Ferrandon, INSERM U 398, Strasbourg, France; A. Nehlig, PhD, INSERM U 398, Strasbourg, France
RATIONALE: The relationship between prolonged seizures in infancy and the development of temporal lobe epilepsy (TLE) has been debated for decades. It is still not known whether a single insult is sufficient to trigger TLE or if a preexisting lesion or another sensitizing factor like a specific genetic background is necessary to favor the development of TLE. Therefore, we compared the consequences of lithium-pilocarpine status epilepticus (SE) induced in 10- (P10) and 21-day-old rats (P21) in GAERS to those in a strain of non epileptic rats (NE) and studied both the lesions and further occurrence of spontaneous seizures.
METHODS: SE was induced in P10 and P21 GAERS and NE rats by lithium-pilocarpine while control animals of both strains received saline. The animals were sacrificed at 6 days after SE for neuronal counting on Cresyl violet-stained sections while other groups of rats were implanted with cortical and hippocampal electrodes and the occurrence of spontaneous seizures was observed and recorded on the EEG.
RESULTS: In P10 GAERS undergoing SE, the number of neurons was significantly decreased compared to the littermate controls in the piriform cortex and basolateral amygdala while it was increased in hippocampal CA3c area. In P21 GAERS undergoing SE, significant loss of neurons was recorded in lateral thalamus and basolateral amygdala, compared to the littermate controls. In P10 NE or GAERS subjected to SE, no rat became spontaneously epileptic. In P21 GAERS and NE rats subjected to SE, 6 of the 8 GAERS did not become epileptic while this was the case only for 2 of the 11 NE rats. The occurrence of spike-and-wave discharges was not affected by SE.
CONCLUSIONS: Our data show that P10 GAERS undergoing SE exhibit specific changes in their neuronal population, losing cortical neurons and preserving more hippocampal pyramidal neurons at 6 days after the insult. However no P10 GAERS becomes epileptic. A lower number of P21 GAERS develop spontaneous or handling triggered seizures compared to age-matched NE rats. Thus, the genetic background underlying absence epilepsy does not seem to specifically facilitate the development of TLE in rats.
Support: INSERM U 398 and Fondation pour la Recherche Medicale.