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Sarcolemmal phospholipid fatty acid composition and permeability
1Department of Medical Physiology and Biochemistry, University of Stellenbosch Medical School, Tygerberg (Republic of South Africa).
Biochimica Et Biophysica Acta
|June 22, 1988
Summary
Myocardial ischemia increases sarcolemmal permeability, leading to enzyme release. Fatty acid perfusion, not just unsaturation, impacts this, suggesting other sarcolemmal changes are involved.
Area of Science:
- Cardiovascular Physiology
- Cell Membrane Biology
- Biochemistry
Background:
- Ischemia-induced myocardial injury involves increased sarcolemmal permeability.
- Sarcolemmal phospholipid composition alterations may contribute to this permeability change.
Purpose of the Study:
- Investigate the mechanism of ischemia-induced increased sarcolemmal permeability.
- Evaluate the role of sarcolemmal phospholipid bilayer changes by modulating fatty acid composition.
Main Methods:
- Isolated perfused rat heart model of global ischemia (low-flow hypoxia).
- Perfusion with glucose, palmitate (saturated fatty acid), or linoleate (unsaturated fatty acid).
- Measurement of lactate dehydrogenase release and sarcolemmal phospholipid fatty acid composition.
Main Results:
- Fatty acid perfusion (palmitate, linoleate) increased lactate dehydrogenase release compared to glucose, under both control and ischemic conditions.
- Fatty acid perfusion led to increased sarcolemmal phospholipid fatty acid unsaturation.
- Enzyme release was also stimulated in control fatty acid-perfused hearts, independent of increased unsaturation.
Conclusions:
- Myocardial ischemia affects sarcolemmal permeability through mechanisms beyond just phospholipid fatty acid composition changes.
- Other sarcolemmal alterations, such as cholesterol loss, may also influence macromolecule permeability during ischemia.