title: [Modification of the structure of plasmatic membranes of the liver by the action of alpha-tocopherol in vitro].
abstract: The effect of the natural antioxidant alpha-tocopherol in a broad concentration range (10(-4) - 10(-25) M) on the viscosity characteristics and thermally induced structural transitions of a lipid bilayer of plasma membranes of murine hepatocytes in vitro has been studied. Changes in the rigidity of surface (approximately Abb) of the lipid bilayer were measured on a Bruker EMX EPR spectrometer (Germany) by the method of spin probes. Stable nitroxyl radicals of 5- and 16-doxylstearic acid, localized at different depth in the membrane served as spin probes. It was shown that the concentration dependence of the effect of alpha-tocopherol is linear and polymodal with three statistically significant increases in three ranges of its concentration: (1) in the range of traditional physiological concentrations 10(-4)-10(-9) M, (2) in the range of superlow doses 10(-9) - 10(-17) M, and (3) in the range of "imaginary" concentrations 10(-17) - 10(-25) M. The mechanisms of action of alpha-tocopherol in each of the three ranges are discussed. When studying the temperature dependences of viscous characteristics, a new thermally induced structural transition in the range of "physiological" temperatures 309-313 K for those alpha-tocopherol concentrations (including superlow ones) to which the maxima on the dose dependence curves at constant temperature of 293 K corresponded.
authors.forename: V V
authors.initials: VV
authors.lastname: Belov
authors.forename: E L
authors.initials: EL
authors.lastname: Mal'tseva
authors.forename: N P
authors.initials: NP
authors.lastname: Pal'mina
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D005609:Free Radicals / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism*; D008099:Liver; D051379:Mice; D014815:Vitamins / Q000494:pharmacology*; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D005609:Free Radicals; D008051:Lipid Bilayers; D014815:Vitamins; D024502:alpha-Tocopherol