Genetic Models of Absence Epilepsy in the Rat

Lipopolysaccharide induced increase in seizure activity in two animal models of absence epilepsy WAG/Rij and GAERS rats and Long Evans rats

“…The genetically absence epileptic WAG/Rij rats and GAERS rats are well established models of human absence epilepsy (Depaulis and Van Luijtelaar, 2005;Van Luijtelaar et al, 2011). It is interesting to note that not only WAG/Rij rats and GAERS rats but also Long Evans rats produce SWDs: spontaneous high-voltage rhythmic spike (HVRS) discharges of Long Evans rats in EEG recordings may be considered as SWDs as was demonstrated by analysis of pharmacological, behavioral and EEG features of HVRS activity (Depaulis and Van Luijtelaar, 2005;Huang et al, 2012;Polack and Charpier, 2006;Shaw, 2004Shaw, , 2007Shaw et al, 2009;Van Luijtelaar et al, 2011).…”

“…1b, d and f), amplitude 0.2-1.0/0.3-1.0/0.1-2.0 mV, duration 1-30/5-60/1-40 s (Akman et al, 2010;Coenen and Van Luijtelaar, 2003;Depaulis and Van Luijtelaar, 2005;Polack and Charpier, 2006;Shaw, 2004). The number of SWDs may vary between 15-40/20-80/6-90 (per hour) in WAG/Rij rats, GAERS rats and Long Evans rats depending on the time of the day and age of animals (Akman et al, 2010;Coenen and Van Luijtelaar, 2003;Depaulis and Van Luijtelaar, 2005;Polack and Charpier, 2006;Shaw, 2004). To avoid the modulatory effect of age and sleep-wake cycle on SWD number, electrophysiological recordings were carry out on eight months old animals (±1 week) between 4.00 PM and 8.00 PM.…”

“…Both i.p. injection and handling evoked stress could influence SWD number during first 30 min (Depaulis and Van Luijtelaar, 2005;Kovács et al, 2006Kovács et al, , 2012. Consequently, the first half hour of data after the i.p.…”

“…Systemic injection of LPS to rats is a well-studied and described way for precipitation of inflammatory reactions in the CNS (Vezzani and Granata, 2005), which is also suitable for investigation of links between immune system and absence epileptic activity (Kovács et al, 2006). Lipopolysaccharide injected into genetically absence epileptic animals such as WAG/Rij rats, the animal strain, which is one of the most appropriate animal model strains for the study of spontaneous childhood absence epilepsy (Depaulis and Van Luijtelaar, 2005), could provide an opportunity for the investigation of the relationships between non-convulsive types of epilepsies such as absence epilepsy and LPS/cytokine evoked neuroinflammatory processes (Kovács et al, 2006), which is still incompletely understood. We previously demonstrated that i.p.…”

“…However, the effects of LPS on absence epileptic activity in freely moving animals have not been investigated in genetically epileptic GAERS rats and Long Evans rats. It was recently demonstrated that Long Evans rats also produce SWDs similarly to WAG/Rij rats and GAERS rats (Depaulis and Van Luijtelaar, 2005;Huang et al, 2012;Polack and Charpier, 2006;Shaw, 2004Shaw, , 2007Shaw et al, 2009;Van Luijtelaar et al, 2011) allowing the investigation of SWDs in this strain as well. Therefore, to validate and extend our previous results, in which we demonstrated the LPS induced increase in absence epileptic seizures in WAG/Rij rats (Kovács et al, 2006) we injected two doses of LPS (50 g/kg and 350 g/kg i.p.)…”