Comparative immunohistochemistry of synaptic markers in the rodent hippocampus in pilocarpine epilepsy

Norbert Károly, A. Mihály, Endre Dobó

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Pilocarpine-induced epileptic state (Status epilepticus) generates an aberrant sprouting of hippocampal mossy fibers, which alter the intrahippocampal circuits. The mechanisms of the synaptic plasticity remain to be determined. In our studies in mice and rats, pilocarpine-induced seizures were done in order to gain information on the process of synaptogenesis. After a 2-month survival period, changes in the levels of synaptic markers (GAP-43 and Syn-I) were examined in the hippocampus by means of semi-quantitative immunohistochemistry. Mossy fiber sprouting (MFS) was examined in each brain using Timm's sulphide-silver method. Despite the marked behavioral manifestations caused by pilocarpine treatment, only 40% of the rats and 56% of the mice showed MFS. Pilocarpine treatment significantly reduced the GAP-43 immunoreactivity in the inner molecular layer in both species, with some minor differences in the staining pattern. Syn-I immunohistochemistry revealed species differences in the sprouting process. The strong immunoreactive band of the inner molecular layer in rats corresponded to the Timm-positive ectopic mossy fibers. The staining intensity in this layer, representing the ectopic mossy fibers, was weak in the mouse. The Syn-I immunoreactivity decreased significantly in the hilum, where Timm's method also demonstrated enhanced sprouting. This proved that, while sprouted axons displayed strong Syn-I staining in rats, ectopic mossy fibers in mice did not express this synaptic marker. The species variability in the expression of synaptic markers in sprouted axons following pilocarpine treatment indicated different synaptic mechanisms of epileptogenesis.

Original languageEnglish
Pages (from-to)656-662
Number of pages7
JournalActa Histochemica
Volume113
Issue number6
DOIs
Publication statusPublished - Oct 2011

Fingerprint

Pilocarpine
Rodentia
Epilepsy
Hippocampus
Immunohistochemistry
GAP-43 Protein
Staining and Labeling
Axons
Hippocampal Mossy Fibers
Neuronal Plasticity
Status Epilepticus
Seizures
Therapeutics
Brain

Keywords

  • Hippocampus
  • Mice
  • Mossy fibers
  • Pilocarpine
  • Rats
  • Seizures
  • Synaptic markers

ASJC Scopus subject areas

  • Cell Biology
  • Histology

Cite this

Comparative immunohistochemistry of synaptic markers in the rodent hippocampus in pilocarpine epilepsy. / Károly, Norbert; Mihály, A.; Dobó, Endre.

In: Acta Histochemica, Vol. 113, No. 6, 10.2011, p. 656-662.

Research output: Contribution to journalArticle

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