Abstracts

Rationale: The sleep deprivation is a powerful activator of epileptic seizures in nearly all types of epilepsy. Despite the unquestionable sensibility of several types of epilepsy to sleep deprivation, innumerous aspects concerned with this deleterious association are unknown. Although basic researches have provided some underlying mechanisms between sleep deprivation and generalized epilepsy, few efforts have been addressed to achieve the exactly function of paradoxical sleep (PS) in absence epilepsy. Furthermore, some studies have suggested that the PS could be an anti-epileptogenic sleep phase (Med Hypotheses 2004;63(1):76-9). The aim of this study was to investigate the paradoxical sleep deprivation (PSD) effects on the occurrence and distribution of seizures throughout the sleep-wakefulness cycle (SWC) in a new form of spontaneous epilepsy which presents seizures similar to the generalized absence epilepsy. Methods: Wistar male rats (N=8) with spontaneous epilepsy (GEASV-rats) were implanted under ketamine anesthesia with nichrome electrodes (150 µm in diameter) over somatosensorial cortical area and hippocampal field CA1 for 24hours electrophysiological recordings pre and post-paradoxical sleep deprivation. The electro-oscillographic analyzes and also sleep-wakefulness characterization was performed according to Timo-Iaria et.al. (Physiol Behav 1970 Sep;5(9):1057-62). The 24 hours PSD was carried out by using a single platform ("flower pot" technique). Repeated-measure analyzes of variances were performed, with p<0.05 as statistically significant. Results: Absence seizures expressed as spike-wave discharges (SWDs) occurred in both, cortex and hippocampus; the occurrence of SWD was higher during relaxed wakefulness (RW) compared to the other phases of SWC before (p<0,001) and, although the SWDs have decreased significantly they are still prevalent in the RW (p<0,001) after PSD; the PSD exerted strong effects over SWDs thus reducing significantly their occurrence throughout the SWC (p<0.001) independently of light/dark photoperiod