Depolarization thresholds for hippocampal damage, ischemic preconditioning, and changes in gene expression after global ischemia in the rat

Issam A. Halaby, Yoshimasa Takeda, Katsumi Yufu, Thaddeus S. Nowak, William A. Pulsinelli

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Induced ischemic tolerance in rat hippocampus was investigated in a forebrain ischemia model of repeated 4-vessel occlusion (4-VO). Ischemic insult variability was reduced by the use of dc potential measurements to determine the duration of ischemic depolarization in hippocampus. The results demonstrate a depolarization threshold for ischemic injury to CA1 neurons of 4-6 min and a window for optimal preconditioning of 2.5-3.5 min. Levels of induced mRNAs encoding hsp72 and several immediate-early genes were also shown to vary with depolarization interval. Immediate-early genes were maximally induced after depolarization periods inducing optimal preconditioning, while hsp72 expression increased with insult severity over the range leading to neuron loss. These results are similar to those obtained in gerbil studies indicating that preconditioning does not require large increases in hsp72 expression, and demonstrate the fundamental comparability of rodent global ischemia models when monitored by this approach.

Original languageEnglish
Pages (from-to)12-16
Number of pages5
JournalNeuroscience Letters
Volume372
Issue number1-2
DOIs
Publication statusPublished - Nov 30 2004
Externally publishedYes

Keywords

  • Gene expression
  • Hippocampus
  • Ischemia
  • Ischemic depolarization
  • Preconditioning
  • Tolerance

ASJC Scopus subject areas

  • Neuroscience(all)

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