Differential hippocampal protection when blocking intracellular sodium and calcium entry during traumatic brain injury in rats

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25 Scopus citations

Abstract

This study investigated the contributions of the reverse mode of the sodium-calcium exchanger (NCX) and the type 1 sodium-proton antiporter (NHE-1) to acute astrocyte and neuronal pathology in the hippocampus following fluid percussion traumatic brain injury (TBI) in the rat. KB-R7943, EIPA, or amiloride, which respectively inhibit NCX, NHE-1, or NCX, NHE-1, and ASIC1a (acid-sensing ion channel type 1a), was infused intraventricularly over a 60-min period immediately prior to TBI. Astrocytes were immunostained for glial fibrillary acidic protein (GFAP), and degenerating neurons were identified by Fluoro-Jade staining at 24 h after injury. Stereological analysis of the CA2/3 sub-regions of the hippocampus demonstrated that higher doses of KB-R7943 (2 and 20 nmoles) significantly reduced astrocyte GFAP immunoreactivity compared to vehicle-treated animals. EIPA (2-200 nmoles) did not alter astrocyte GFAP immunoreactivity. Amiloride (100 nmoles) significantly attenuated the TBI-induced acute reduction in astrocyte GFAP immunoreactivity. Of the three compounds examined, only amiloride (100 nmoles) reduced hippocampal neuronal degeneration assessed with Fluoro-Jade. The results provide additional evidence of acute astrocyte pathology in the hippocampus following TBI, while suggesting that activation of NHE-1 and the reverse mode of NCX contribute to both astrocyte and neuronal pathology following experimental TBI.

Original languageEnglish (US)
Pages (from-to)1195-1205
Number of pages11
JournalJournal of Neurotrauma
Volume25
Issue number10
DOIs
StatePublished - Oct 1 2008

Keywords

  • Astrocyte
  • Glia
  • Hippocampus
  • Ion exchangers
  • Lateral fluid percussion injury
  • Neuronal degeneration
  • Sodium
  • Traumatic brain injury

ASJC Scopus subject areas

  • Clinical Neurology

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