Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers

Journal Article · Thu Jan 08 00:00:00 EST 2015 · Soft Matter

DOI:https://doi.org/10.1039/C4SM02667E· OSTI ID:1172226

Moskovitz, Yevgeny ^[1]; Yang, Hui ^[2]

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1. Middle Tennessee State Univ., Murfreesboro, TN (United States). Dept. of Chemistry; Univ. of Capetown (South Africa). Dept. of Chemistry, Scientific Computing Research Unit
2. Middle Tennessee State Univ., Murfreesboro, TN (United States). Dept. of Chemistry

Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns-long) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules at a pressure range of 1 - 1000 bar and temperature of 310 Kelvin. Xenon and argon have been tested as model gases for general anesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremor at hyperbaric conditions. The analysis of stacked radial pair distribution functions of DOPC headgroup atoms revealed the explicit solvation potential of gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor; while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar patterns of the order parameter for both DOPC acyl chains, which is opposite to the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the ‘critical volume’ hypothesis of anesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1 - 100 bar could be associated with the possible manifestation of neurological tremor at the atomic scale. The non-immobilizer neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing monolayers undulations rate, which indicates enhanced diffusivity, rather than atom size, as the key factor.

• Research Organization: Middle Tennessee State Univ., Murfreesboro, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: SC0005094
• OSTI ID: 1172226
• Journal Information: Soft Matter, Vol. 11, Issue 11; ISSN 1744-683X
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
lipid bilayer
molecular dynamics
general anesthesia
pressure reversal
noble gases
high pressure nervous syndrome