Hyperthermic seizure induces persistent alteration in excitability of the dentate gyrus in immature rats.
Febrile seizure (FS) is the most common type of seizure that occurs during early childhood. It has been proposed that atypical FS (prolonged, multiple, or lateralized) results in the development of recurrent complex partial seizures accompanied by Ammon's horn sclerosis or mesial temporal sclerosis, which is the most common of the intractable epilepsy. To elucidate the characteristics of epileptogenesis or acquired epilepsy following FS, we performed prospective long-term studies using hyperthermia-induced seizure model. Rat pups (postnatal 11 day old) were induced to hyperthermia (41-43 degrees C in core temperature) by exposure to a 175 W mercury vapor lamp. Six-nine weeks after hyperthermic seizure, the dentate gyrus showed impairments of paired-pulse inhibitions and excitability ratio. In addition, newly generated granule cells and synaptogenesis were observed in this region. Ten-twelve weeks after hyperthermic seizure, animals (approximately 68%) showed electroencephalographic seizure activity with increased VGLUT-1 immunoreactivity in the dentate gyrus. Parvalbumin immunoreactivity was markedly reduced in the hilus. These findings indicate that in this model the epileptogenic changes in the dentate gyrus may be based on the persistent alterations in excitability via neurogenesis, synaptogenesis, and impaired GABA(B) receptor-mediated inhibition.
Kwak
Sung-Eun
SE
Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chunchon, Kangwon-Do 200-702, South Korea.
Kim
Ji-Eun
JE
Kim
Sung Chan
SC
Kwon
Oh-Shin
OS
Choi
Soo-Young
SY
Kang
Tae-Cheon
TC
D000818:Animals; D003423:Critical Period, Psychological; D018891:Dentate Gyrus / Q000473:pathology*; D004195:Disease Models, Animal; D004827:Epilepsy / Q000209:etiology* / Q000473:pathology; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D019599:Mossy Fibers, Hippocampal / Q000254:growth & development; D009433:Neural Inhibition; D009474:Neurons / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018080:Receptors, GABA-B / Q000378:metabolism; D003294:Seizures, Febrile / Q000150:complications / Q000473:pathology*; D013569:Synapses / Q000378:metabolism; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism
D018080:Receptors, GABA-B; D050598:Vesicular Glutamate Transport Protein 1