Formation of free choline in brain tissue during in vital energy deprivation

Bogdan Djuricic, Steven R. Olson, Hussein M. Assaf, Tim S. Whittingham, W. David Lust, Lester R Drewes

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Free choline and ATP contents were measured in Mongolian gerbil hippocampal slices (tissue) and incubation media (media) during exposure to 30 min of aglycemia, high potassium, anoxia, or ischemia. Changes in choline levels reflected the degree of energy reduction, lower ATP levels being associated with high choline (4-fold increase during exposure to high potassium and anoxia, and 11-fold increase during ischemia). Media (extracellular) choline was particularly affected and increased about twofold during relatively mild energy depletion (e.g., aglycemia), but tissue choline content was less sensitive to energy reduction. A plot of choline vs. ATP levels indicated a nonlinear correlation, and the sharp increase in choline occurred when ATP values fell to about 2.5 nmol/mg of protein. Inhibition of acetylcholine sterase by 10 μM physostigmine during ischemia dial not prevent an increase in choline contents but rather enhanced them, indicating that acetylcholine hydrolysis was not the source of free choline. Formation of free choline was Ca2+ independent. These findings suggest the involvement of phospholipase D and phosphatidylcholine hydrolysis in free choline formation during enengy stress. The extent of choline formation may be an indicator of the degree of membranal damage, which in turn reflects damage to the metabolic machinery of the cell.

Original languageEnglish (US)
Pages (from-to)308-313
Number of pages6
JournalJournal of Cerebral Blood Flow and Metabolism
Volume11
Issue number2
DOIs
StatePublished - 1991

Keywords

  • Aglycemia
  • Anoxia-ischemia
  • Energy depletion
  • Free choline
  • High potassium
  • Hippocampal slices

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