Different patterns of neuronal activation and neurodegeneration in the thalamus and cortex of epilepsy-resistant Proechimys rats versus Wistar rats after pilocarpine-induced protracted seizures

Different patterns of neuronal activation and neurodegeneration in the thalamus and cortex of epilepsy-resistant Proechimys rats versus Wistar rats after pilocarpine-induced protracted seizures

Author Andrioli, Anna Google Scholar
Fabene, Paolo F. Google Scholar
Spreafico, Roberto Google Scholar
Cavalheiro, Esper Abrão Autor UNIFESP Google Scholar
Bentivoglio, Marina Google Scholar
Institution Univ Verona
Neurol Inst Carlo Besta
Universidade Federal de São Paulo (UNIFESP)
Abstract To analyze cellular mechanisms of limbic-seizure suppression, the response to pilocarpine-induced seizures was investigated in cortex and thalamus, comparing epilepsy-resistant rats Proechimys guyannensis with Wistar rats.Fos immunoreactivity revealing neuronal activation, and degenerating neurons labeled by Fluoro-Jade B (FJB) histochemistry were analyzed on the first day after onset of seizures lasting 3 h. Subpopulations of gamma-aminobutyric acid (GABA)ergic cells were characterized with double Fos-parvalbumin immunohistochemistry.In both cortex and thalamus, degenerating neurons were much fewer in Proechimys than Wistar rats. Fos persisted at high levels at 24 h only in the Proechimys thalamus and cortex, especially in layer VI where corticothalamic neurons reside. in the parietal cortex, about 50% of parvalbumin-containing interneurons at 8 h, and 10-20% at 24 h, were Fos-positive in Wistar rats, but in Proechimys, Fos was expressed in almost all parvalbumin-containing interneurons at 8 h and dropped at 24 h. Fos positivity in cingulate cortex interneurons was similar in both species. in the Wistar rat thalamus, Fos was induced in medial and midline nuclei up to 8 h, when < 30% of reticular nucleus cells were Fos-positive, and then decreased, with no relationship with cell loss, evaluated in Nissl-stained sections. in Proechimys, almost all reticular nucleus neurons were Fos-positive at 24 h.At variance with laboratory rats, pilocarpine-induced protracted seizures elicit in Proechimys limited neuronal death, and marked and long-lasting Fos induction in excitatory and inhibitory cortical and thalamic cell subsets. the findings implicate intrathalamic and intracortical regulation, and circuits linking thalamus and cortex in limbic seizure suppression leading to epilepsy resistance.
Keywords Fos
Cell death
Thalamic reticular nucleus
Corticothalamic system
Cingulate cortex
Neocortex
Language English
Date 2009-04-01
Published in Epilepsia. Malden: Wiley-Blackwell Publishing, Inc, v. 50, n. 4, p. 832-848, 2009.
ISSN 0013-9580 (Sherpa/Romeo, impact factor)
Publisher Wiley-Blackwell
Extent 832-848
Origin http://dx.doi.org/10.1111/j.1528-1167.2008.01953.x
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000264821700025
URI http://repositorio.unifesp.br/handle/11600/31398

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