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Molecular dynamics simulation of anesthetic-phospholipid bilayer interactions
P Huang1, E Bertaccini, G H Loew
1Molecular Research Institute, Palo Alto, CA 94304, USA.
Journal of Biomolecular Structure & Dynamics
|February 1, 1995
Summary
General anesthetics like trichloroethylene (TCE) alter lipid bilayer properties, increasing fluidity and promoting hexagonal phase formation. These effects are reversed by increased pressure, supporting the lipid-mediated mechanism of anesthetic action.
Area of Science:
- Biophysics
- Molecular Pharmacology
- Membrane Biophysics
Background:
- General anesthetics are thought to act via a lipid-mediated mechanism.
- Understanding molecular interactions between anesthetics and lipid bilayers is crucial.
Purpose of the Study:
- To investigate the effects of trichloroethylene (TCE) on a dioleoylphosphatidylcholine (DOPC) lipid bilayer at a molecular level.
- To elucidate the interaction of bioactive compounds with biological membranes.
Main Methods:
- Molecular dynamics (MD) simulations of a DOPC lipid bilayer with a single TCE molecule at 37°C and 1 atm.
- Comparison of simulation results with experimental 31P and 2H NMR data.
- MD simulations were also performed at elevated pressures (200 and 400 atm) to study pressure antagonism.
Main Results:
- TCE increased the ratio of hydrocarbon tail area to head group area, suggesting a tendency to form hexagonal phase (HII).
- TCE slightly increased gauche conformation frequency in lipid chains and significantly increased lateral diffusion, indicating increased membrane fluidity.
- These effects were partially prevented at 200 atm and blocked at 400 atm, showing pressure reversibility.
Conclusions:
- TCE perturbs lipid bilayers by increasing fluidity and promoting HII phase formation.
- The pressure-dependent reversal of these effects supports their relevance to general anesthesia's pressure antagonism.
- Findings provide molecular insights into general anesthetic-membrane interactions.