EXTRACELLULAR IONIC AND PH REGULATION

Project: Research project

Project Details

Description

The first response of the spinal cord to traumatic insult is a rapid
breakdown of ion homeostasis. The resultant ion shifts persist for hours,
and have been implicated in several models of cellular injury. The broad
objective of this study is to elucidate the mechanisms which initiate and
prolong these ionic derangements. Experiments will utilize ion-selective
microelectrode techniques to quantity the magnitude and time course of
extracellular ion shifts following graced contusion injured of the rat
spinal cord. Initial studies will address derangements of extracellular
calcium, potassium, sodium, chloride, bicarbonate and pH, with emphasis on
the biophysics of ion diffusion in an around the injury site. We will then
focus on the acid-base status of the injured spinal cord, to address the
role of blood glucose and focal ischemia in the evolution of acute acidosis
and secondary injury. Extracellular pH, blood flow and tissue lactate will
be measured in hyperglycemic, normoglycemic and hypoglycemic animals,
following spinal cord injury. A similar protocol will be utilized in a
four week chronic study, to determine the role of these factors in
electrophysiologic and histologic outcome. In the final year, the
activity-dependent shifts of extracellular pH and volume will be studied in
chronic spinal cord injury. These experiments will focus on the role of
reactive glial cells in the modulation of extracellular fluid composition
around the chronic lesion site. This project will provide the first
detailed characterization of extracellular ion dynamics in spinal cord
injury. Information obtained will provide important insights into the
mechanisms of acute and chronic spinal dysfunction, and will serve to test
and amplify current hypotheses of cellular injury.
StatusFinished
Effective start/end date1/1/013/31/99

Funding

  • National Institute of Neurological Disorders and Stroke
  • National Institute of Neurological Disorders and Stroke
  • National Institute of Neurological Disorders and Stroke

ASJC

  • Clinical Neurology
  • Neurology
  • Biotechnology
  • Physiology
  • Neuroscience(all)

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