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On the relationship between alcohol narcosis and membrane fluidity
Substance and Alcohol Actions/Misuse
|January 1, 1982
Summary
Temperature significantly impacts alcohol narcosis in fish. While increased temperature and ethanol raise membrane fluidity, fluidity itself doesn't cause narcosis, but membrane structure influences alcohol sensitivity.
Area of Science:
- Environmental toxicology
- Neuroscience
- Biochemistry
Background:
- Alcohol narcosis, characterized by loss of righting reflex, is influenced by environmental factors.
- Membrane fluidity is a key factor in cellular function and response to external stimuli.
- Understanding alcohol's effects on aquatic organisms is crucial for ecological assessments.
Purpose of the Study:
- To investigate the relationship between membrane fluidity and alcohol-induced narcosis in fish at varying temperatures.
- To determine if changes in membrane fluidity are the primary cause of alcohol narcosis.
- To explore the role of temperature adaptation in alcohol sensitivity.
Main Methods:
- Experiments were conducted on the fish Gambusia affinis at different temperatures.
- Ethanol and hexanol were used to induce narcosis, and their potency was assessed.
- Membrane fluidity was measured using diphenyl-hexatriene (DPH) fluorescence anisotropy.
- Fatty acid composition of cell membranes was analyzed in temperature-adapted fish.
Main Results:
- The potency of ethanol and hexanol increased with temperature, and narcosis could be reversed by lowering the temperature.
- Both increased temperature and ethanol increased membrane fluidity, but fluidity changes did not directly correlate with narcosis.
- A 2-degree temperature increase caused a greater fluidity change than narcotic ethanol concentrations; an 8-degree increase did not induce narcosis.
- Temperature-adapted summer fish had higher saturated fatty acids, a wider temperature range, and greater ethanol resistance.
Conclusions:
- The increase in bulk membrane fluidity caused by ethanol is not the direct cause of narcosis.
- Membrane structure, influenced by factors like temperature adaptation and fatty acid composition, plays a significant role in determining alcohol sensitivity.
- Alcohol sensitivity in fish is a complex trait influenced by both acute temperature changes and long-term adaptation.