Spontaneous epileptic rats show changes in sleep architecture and hypothalamic pathology

Purpose: The goal of the present study was to investigate the relationship between sleep, hypothalamic pathology, and seizures in spontaneous epileptic rats. Methods: Rats were implanted with radiotelemetry transmitters for measuring electrocorticogram (ECoG) and stimulation electrodes in the hippocampus. Epileptogenesis was triggered by 2 h of electical stimulation-induced self-sustained status epilepticus (SSSE). After SSSE, ECoGs were monitored over a 15-week period for the occurrence of interictal high-amplitude low-frequency (HALF) activity and spontaneous reoccurring seizures (SRSs). Results: Spontaneous epileptic rats showed clinical features of temporal lobe epilepsy (TLE), such as spontaneous seizures, interictal activity and neuronal cell loss in the dorsomedial hypothalamus, a region important for normal sleep regulation. Interestingly, epileptic rats showed disturbances in sleep architecture, with a high percentage of the seizures occurring during sleep. Conclusions: Therefore we conclude that a close association exists between epileptiform activity and alterations in sleep architecture that may be related to hypothalamic pathology.