A significant increase in both basal and maximal calcineurin activity following fluid percussion injury in the rat

Jonathan E. Kurz, J. Travis Parsons, Aniruddha Rana, Cynthia J. Gibson, Robert J. Hamm, Severn B. Churn*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Calcineurin, a neuronally enriched, calcium-stimulated phosphatase, is an important modulator of many neuronal processes, including several that are physiologically related to the pathology of traumatic brain injury. This study examined the effects of moderate, central fluid percussion injury on the activity of this important neuronal enzyme. Animals were sacrificed at several time-points post-injury and cortical, hippocampal, and cerebellar homogenates were assayed for calcineurin activity by dephosphorylation of p-nitrophenol phosphate. A significant brain injury-dependent increase was observed in both hippocampal and cortical homogenates under both basal and maximally-stimulated reaction conditions. This increase persisted 2-3 weeks post-injury. Brain injury did not alter substrate affinity, but did induce a significant increase in the apparent maximal dephosphorylation rate. Unlike the other brain regions, no change in calcineurin activity was observed in the cerebellum following brain injury. No brain region tested displayed a significant change in calcineurin enzyme levels as determined by Western blot, demonstrating that increased enzyme synthesis was not responsible for the observed increase in activity. The data support the conclusion that fluid percussion injury results in increased calcineurin activity in the rat forebrain. This increased activity has broad physiological implications, possibly resulting in altered cellular excitability or a greater likelihood of neuronal cell death.

Original languageEnglish (US)
Pages (from-to)476-490
Number of pages15
JournalJournal of neurotrauma
Volume22
Issue number4
DOIs
StatePublished - Apr 2005

Keywords

  • Calcium
  • Calmodulin
  • Hippocampus
  • Phosphatase
  • Post-translational modification

ASJC Scopus subject areas

  • Clinical Neurology

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