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Chronic ethanol treatment affects synaptosomal membrane-bound enzymes
Pharmacology, Biochemistry, and Behavior
|January 1, 1983
Summary
Chronic ethanol exposure alters brain enzyme activity and membrane properties, leading to adaptive changes that confer resistance to alcohol
Area of Science:
- Neurochemistry
- Biochemistry
- Pharmacology
Background:
- Ethanol consumption affects brain function.
- Chronic alcohol intake induces adaptive changes in cellular membranes.
Purpose of the Study:
- Investigate the impact of chronic ethanol administration on brain membrane-bound enzyme activity.
- Examine changes in membrane physical properties and enzyme stability.
Main Methods:
- Enzyme activity assays (Na+, K+-ATPase, Ca++ ATPase, 5'-nucleotidase, acetylcholinesterase, adenylate cyclase).
- Arrhenius plot analysis of synaptosomal enzymes.
- Fluorescence spectroscopy using l-anilinonaphthalene-8-sulfonate (ANS).
- Enzyme stability assays with detergents.
Main Results:
- Progressive increase in brain membrane-bound enzyme activities after 2 and 4 weeks of ethanol.
- Altered transition temperatures in synaptosomal enzymes from ethanol-treated rats.
- Ethanol induced less fluorescence quenching in membranes from habituated rats.
- Enzymes from ethanol-habituated rats showed increased stability.
Conclusions:
- Chronic ethanol administration induces protein conformation changes in brain membranes.
- Altered membrane lipid properties contribute to these changes.
- Membranes from ethanol-habituated animals exhibit resistance to ethanol's effects, potentially underlying tolerance and dependence.