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Increased Activity of Ca 2+ ‐Dependent Enzymes of Membrane Lipid Metabolism in Synaptosomal Preparations from Ethanol‐Dependent Rats
Author(s) -
John G. R.,
Littleton J. M.,
Nhamburo P. T.
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb08749.x
Subject(s) - ethanol , enzyme , chemistry , phospholipid , synaptosome , phospholipase , in vivo , biochemistry , in vitro , enzyme assay , metabolism , phospholipase a2 , lipid metabolism , membrane , biology , microbiology and biotechnology
In synaptosomal fractions of rat brain the activities of phospholipase A 2 and the phospholipid base exchange enzymes are highly dependent on external Ca 2+ concentrations. Their activity is inhibited by the presence of 50 m M ethanol in vitro. Administration of ethanol to rats by inhalation causes a progressive increase in the activity of these enzymes in synaptosomal preparations at all Ca 2+ concentrations studied. The increased activity of these enzymes persists in preparations from rats undergoing a physical syndrome of withdrawal from ethanol. The addition of ethanol in vitro to preparations from animals that had received ethanol in vivo had no significant effect on enzyme activity. The results are discussed in relation to the possible roles of membrane lipid metabolism and synaptic Ca 2+ sensitivity in ethanol tolerance and physical dependence.