Anaesthetic Mechanism on a Model Biological Membrane: A Molecular Dynamics Simulation Study

We study the effects of anaesthetic molecules at surgical concentration on a biological membrane model, in an attempt to elucidate the mechanism by which the anaesthetic interacts with the membrane. Using a molecular dynamics simulation of benzyl alcohol molecules embedded in a lipid membrane, we detected no relevant structural change in the hydrocarbon region of the membrane that might explain the action mechanism of the anaesthetic. Only a slight increase in the disorder of the membrane in the deepest zones of the hydrocarbon region was measured from our simulations in the presence of benzyl alcohol. No variation in the thickness of the membrane, surface area per lipid molecule, or atom distribution across the membrane was detected from our simulations when the anaesthetic was embedded in the interior of the membrane. On the other hand, there was clear anisotropy in the rotational and translational diffusion coefficients of the benzyl alcohol molecules in the interior of the membrane.