Diffuse brain injury elevates tonic glutamate levels and potassium-evoked glutamate release in discrete brain regions at two days post-injury: An enzyme-based microelectrode array study

Jason M. Hinzman, Theresa Currier Thomas, Jason J. Burmeister, Jorge E. Quintero, Peter Huettl, Francois Pomerleau, Greg A. Gerhardt, Jonathan Lifshitz

Research output: Contribution to journalArticle

84 Citations (Scopus)

Abstract

Traumatic brain injury (TBI) survivors often suffer from a wide range of post-traumatic deficits, including impairments in behavioral, cognitive, and motor function. Regulation of glutamate signaling is vital for proper neuronal excitation in the central nervous system. Without proper regulation, increases in extracellular glutamate can contribute to the pathophysiology and neurological dysfunction seen in TBI. In the present studies, enzyme-based microelectrode arrays (MEAs) that selectively measure extracellular glutamate at 2Hz enabled the examination of tonic glutamate levels and potassium chloride (KCl)-evoked glutamate release in the prefrontal cortex, dentate gyrus, and striatum of adult male rats 2 days after mild or moderate midline fluid percussion brain injury. Moderate brain injury significantly increased tonic extracellular glutamate levels by 256% in the dentate gyrus and 178% in the dorsal striatum. In the dorsal striatum, mild brain injury significantly increased tonic glutamate levels by 200%. Tonic glutamate levels were significantly correlated with injury severity in the dentate gyrus and striatum. The amplitudes of KCl-evoked glutamate release were increased significantly only in the striatum after moderate injury, with a 249% increase seen in the dorsal striatum. Thus, with the MEAs, we measured discrete regional changes in both tonic and KCl-evoked glutamate signaling, which were dependent on injury severity. Future studies may reveal the specific mechanisms responsible for glutamate dysregulation in the post-traumatic period, and may provide novel therapeutic means to improve outcomes after TBI.

Original languageEnglish (US)
Pages (from-to)889-899
Number of pages11
JournalJournal of Neurotrauma
Volume27
Issue number5
DOIs
StatePublished - May 1 2010
Externally publishedYes

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Microelectrodes
Glutamic Acid
Wounds and Injuries
Brain
Enzymes
Dentate Gyrus
Brain Injuries
Diffuse Brain Injury
Percussion
Potassium Chloride
Prefrontal Cortex
Cognition
Central Nervous System

Keywords

  • Amperometry
  • Hippocampus
  • Microdialysis
  • Synaptic release

ASJC Scopus subject areas

  • Clinical Neurology

Cite this

Diffuse brain injury elevates tonic glutamate levels and potassium-evoked glutamate release in discrete brain regions at two days post-injury : An enzyme-based microelectrode array study. / Hinzman, Jason M.; Thomas, Theresa Currier; Burmeister, Jason J.; Quintero, Jorge E.; Huettl, Peter; Pomerleau, Francois; Gerhardt, Greg A.; Lifshitz, Jonathan.

In: Journal of Neurotrauma, Vol. 27, No. 5, 01.05.2010, p. 889-899.

Research output: Contribution to journalArticle

Hinzman, Jason M. ; Thomas, Theresa Currier ; Burmeister, Jason J. ; Quintero, Jorge E. ; Huettl, Peter ; Pomerleau, Francois ; Gerhardt, Greg A. ; Lifshitz, Jonathan. / Diffuse brain injury elevates tonic glutamate levels and potassium-evoked glutamate release in discrete brain regions at two days post-injury : An enzyme-based microelectrode array study. In: Journal of Neurotrauma. 2010 ; Vol. 27, No. 5. pp. 889-899.
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