A subconvulsive dose of kainate selectively compromises astrocytic metabolism in the mouse brain in vivo

J Cereb Blood Flow Metab. 2014 Aug;34(8):1340-6. doi: 10.1038/jcbfm.2014.88. Epub 2014 May 14.

Abstract

Despite the well-established use of kainate as a model for seizure activity and temporal lobe epilepsy, most studies have been performed at doses giving rise to general limbic seizures and have mainly focused on neuronal function. Little is known about the effect of lower doses of kainate on cerebral metabolism and particularly that associated with astrocytes. We investigated astrocytic and neuronal metabolism in the cerebral cortex of adult mice after treatment with saline (controls), a subconvulsive or a mildly convulsive dose of kainate. A combination of [1,2-(13)C]acetate and [1-(13)C]glucose was injected and subsequent nuclear magnetic resonance spectroscopy of cortical extracts was employed to distinctively map astrocytic and neuronal metabolism. The subconvulsive dose of kainate led to an instantaneous increase in the cortical lactate content, a subsequent reduction in the amount of [4,5-(13)C]glutamine and an increase in the calculated astrocytic TCA cycle activity. In contrast, the convulsive dose led to decrements in the cortical content and (13)C labeling of glutamate, glutamine, GABA, and aspartate. Evidence is provided that astrocytic metabolism is affected by a subconvulsive dose of kainate, whereas a higher dose is required to affect neuronal metabolism. The cerebral glycogen content was dose-dependently reduced by kainate supporting a role for glycogen during seizure activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / drug effects
  • Astrocytes / metabolism*
  • Brain / drug effects
  • Brain / metabolism*
  • Citric Acid Cycle / drug effects
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Epilepsy / chemically induced
  • Epilepsy / metabolism*
  • Glutamine / metabolism
  • Kainic Acid / administration & dosage*
  • Kainic Acid / pharmacology*
  • Lactates / metabolism
  • Magnetic Resonance Spectroscopy
  • Male
  • Mice
  • Mice, Inbred C57BL

Substances

  • Lactates
  • Glutamine
  • Kainic Acid