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Type: Artigo de periódico
Title: Concentration Effects Of Volatile Anesthetics On The Properties Of Model Membranes: A Coarse-grain Approach.
Author: Pickholz, Mónica
Saiz, Leonor
Klein, Michael L
Abstract: To gain insights into the molecular level mechanism of drug action at the membrane site, we have carried out extensive molecular dynamics simulations of a model membrane in the presence of a volatile anesthetic using a coarse-grain model. Six different anesthetic (halothane)/lipid (dimyristoylphosphatidylcholine) ratios have been investigated, going beyond the low doses typical of medical applications. The volatile anesthetics were introduced into a preassembled fully hydrated 512-molecule lipid bilayer and each of the molecular dynamics simulations were carried out at ambient conditions, using the NPT ensemble. The area per lipid increases monotonically with the halothane concentration and the lamellar spacing decreases, whereas the lipid bilayer thickness shows no appreciable differences and only a slight increase upon addition of halothane. The density profiles of the anesthetic molecules display a bimodal distribution along the membrane normal with maxima located close to the lipid-water interface region. We have studied how halothane molecules fluctuate between the two maxima of the bimodal distribution and we observed a different mechanism at low and high anesthetic concentrations. Through the investigation of the reorientational motions of the lipid tails, we found that the anesthetic molecules increase the segmental order of the lipids close to the membrane surface.
Subject: Anesthetics, Inhalation
Computer Simulation
Lipid Bilayers
Macromolecular Substances
Membrane Fluidity
Membranes, Artificial
Models, Chemical
Models, Molecular
Molecular Conformation
Citation: Biophysical Journal. v. 88, n. 3, p. 1524-34, 2005-Mar.
Rights: aberto
Identifier DOI: 10.1529/biophysj.104.044354
Date Issue: 2005
Appears in Collections:Unicamp - Artigos e Outros Documentos

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