Stroke, Vol 18, 418-425, Copyright © 1987 by American Heart Association
J Bralet, P Beley, R Jemaa, AM Bralet and A Beley
Multiple infarcts were produced in cerebral hemispheres of rats by
injecting calibrated 50-micron microspheres into the left internal carotid
artery, and alterations in lipid and energy metabolism were evaluated 24
hours later in the embolized hemisphere. Total phospholipid content was
decreased by 26%, but the different classes of phospholipids were not
equally affected. Phosphatidylinositol and phosphatidylserine levels were
decreased by about 40% and phosphatidylcholine and phosphatidylethanolamine
by 25%, while sphingomyelin level remained unchanged. There was a 3.2-fold
increase in total free fatty acid content with a relatively larger rise in
polyunsaturated free fatty acids 20:4 and 22:6 (20-fold increase).
Determination of enzyme activities showed decreases in Na+,K+-ATPase (-
21%) and hexokinase (-14%) but no changes in phosphofructokinase and
pyruvate kinase. Study of energy metabolism using the closed system method
of Lowry et al showed a significant depression (-36%) of the cerebral
metabolic rate. Taken together, these data suggest a relation between lipid
alterations and dysfunction of energy metabolism. Phospholipid degradation
with subsequent free fatty acid release and alteration in membrane-bound
enzymes may have a direct effect on metabolic machinery and may slow
cerebral metabolic rate.
ARTICLES
Lipid metabolism, cerebral metabolic rate, and some related enzyme activities after brain infarction in rats
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