Temporal changes in proton MRS metabolites after kainic acid-induced seizures in rat brain

I. M. Najm, Y. Wang, S. C. Hong, H. O. Lüders, T. C. Ng, Y. G. Comair

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: In situ 1H-magnetic resonance spectroscopy (MRS) was used to study temporal metabolic changes in a rat model of temporal lobe epilepsy (TLE) by using kainic acid (KA). Methods: Rat brains were scanned at the level of the hippocampal body for MRS measurements. Relative ratios of N- acetyl groups (NA: N-acetylaspartate and N-acetylaspartyl glutamate), choline, and lactate (Lac) over creatine (Cr) were calculated. Results: NA/Cr ratios increased significantly during the ictal phase. During the postictal and interictal phases, the NA/Cr ratio decreased. There was a significant and prolonged increase of the lactate/Cr ratio in the hippocampi of rats that started 1 h after the onset of KA-induced seizure activity and persisted up to 24 h after the injection. The prolonged lactate/Cr increase in an area susceptible to neuronal damage (e.g., hippocampus) correlated with the onset of seizure activity but remained elevated thereafter. Conclusions: The ictal and early postictal increase in lactate ratios may reflect increased cellular activity and metabolism resulting from KA excitotoxicity. Assuming that the changes in NA/Cr ratios are due to NAA increase, we speculate that an activation of the N-acetylaspartylglutamate (NAAG) dipeptidase pathway may explain the ictal increase in NA/Cr ratios. The late postictal decrease in NA/Cr ratios is a reflection of KA-induced neuronal cell loss.

Original languageEnglish (US)
Pages (from-to)87-94
Number of pages8
JournalEpilepsia
Volume38
Issue number1
DOIs
StatePublished - 1997
Externally publishedYes

Keywords

  • Brain
  • Kainic acid
  • MRS
  • Rat
  • Seizure

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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