FEBRILE SEIZURES - AN APPROPRIATE-AGED MODEL SUITABLE FOR LONG-TERM STUDIES

Seizures induced by fever are the most prevalent age-specific seizures in infants and young children. Whether they result in long-term seque lae such as neuronal loss and temporal lobe epilepsy is controversial. Prospective studies of human febrile seizures have found no adverse e ffects on the developing brain. However, adults with temporal lobe epi lepsy and associated limbic cell loss frequently have a history of pro longed febrile seizures in early life. These critical issues may be re solved using appropriate animal models. Published models of hypertherm ic seizures have used 'adolescent' and older rats, have yielded a low percentage of animals with actual seizures, or have suffered from a hi gh mortality, rendering them unsuitable for long-term studies. This ar ticle describes the establishment of a model of febrile seizures using the infant rat. Hyperthermia was induced by a regulated stream of mil dly heated air, and the seizures were determined by both behavioral an d electroencephalographic (EEG) criteria. Stereotyped seizures were ge nerated in 93.6% of 10-11-day-old rats. EEG correlates of these seizur es were not evident in cortical recordings, but were clearly present i n depth recordings from the amygdala and hippocampus. Prolonged febril e seizures could be induced without bums, yielding a low mortality (11 %) and long-term survival. In summary, an infant rat paradigm of EEG-c onfirmed, hyperthermia-induced seizures which is suitable for long-ter m studies is described. This model should be highly valuable for study ing the mechanisms and sequelae of febrile seizures.