Fructose-1,6-bisphosphate stabilizes brain intracellular calcium during hypoxia in rats

Exogenously administered fructose-1,6-bisphosphate reduces neuronal injury from hypoxic or ischemic brain insults. To test the hypothesis that fructose-1,6-bisphosphate prevents changes in intracellular calcium ([Ca2+]i) and high-energy phosphate levels, we measured [Ca2+]i, intracellular pH (pHi),...

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Bibliographic Details
Published in:Stroke (1970) 1992-11, Vol.23 (11), p.1617-1622
Main Authors: Bickler, P E, Kelleher, J A
Format: Article
Language:English
Subjects:
Adenosine Triphosphate - metabolism
Animals
Brain - metabolism
Calcium - metabolism
Fructosediphosphates - pharmacology
Glycolysis - drug effects
Hydrogen-Ion Concentration
Hypoxia - metabolism
Intracellular Membranes - metabolism
Iodoacetates - pharmacology
Iodoacetic Acid
Rats
Rats, Sprague-Dawley
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Summary:Exogenously administered fructose-1,6-bisphosphate reduces neuronal injury from hypoxic or ischemic brain insults. To test the hypothesis that fructose-1,6-bisphosphate prevents changes in intracellular calcium ([Ca2+]i) and high-energy phosphate levels, we measured [Ca2+]i, intracellular pH (pHi), and adenosine triphosphate in cultured rat cortical astrocytes and cortical brain slices during hypoxia. The fluorescent indicators fura-2 and bis-carboxyethyl-carboxyfluorescein were used to simultaneously measure [Ca2+]i and pHi with a fluorometer. Exposure to hypoxia (95% N2, 5% CO2) or 100 microM sodium cyanide produced transient increases in [Ca2+]i in astrocytes and sustained increases in [Ca2+]i in brain slices. Adenosine triphosphate levels fell in slices exposed to hypoxia or cyanide. Fructose-1,6-bisphosphate (3.5 mM) blocked increases in [Ca2+]i and prevented depletion of adenosine triphosphate. Fructose-1,6-bisphosphate also partially prevented adenosine triphosphate depletion in brain slices incubated in glucose-free medium. Iodoacetate (a specific inhibitor of glycolysis) elevated [Ca2+]i and partially prevented these actions of fructose-1,6-bisphosphate. Changes in pHi during hypoxia were not affected by fructose-1,6-bisphosphate. Fructose-1,6-bisphosphate supports adenosine triphosphate production via stimulation of glycolysis and results in the maintenance of normal [Ca2+]i during hypoxia or hypoglycemia.
ISSN:0039-2499
1524-4628
DOI:10.1161/01.str.23.11.1617