title: [The effect of alpha-tocopherol in a wide range of concentrations on the structural features of the lipid bilayer regions of endoplasmic reticulum membranes in the mouse liver cells in vitro].
abstract: The aim of the present work was to study by ESR-spin-probe technique the effect of the natural antioxidant alpha-tocopherol (alpha-tp) in vitro on the structural parameters (microviscosity, order parameter) of endoplasmic reticulum membranes of the mice liver cells starting from the concentration of 10(-3) mol/l and down to the dilution of 10(-25) mol/l. The stable nitroxyl radicals 16-doxylstearic acid (with the deep localization depth of 20 A) and 5-doxylstearic acid (with the surface localization depth of 8 A) were used as spin probes. It has been shown that alpha-tp causes the increase in microviscosity of the deep lipid bilayer regions and in rigidity of the surface ones at the certain concentrations. The concentration curves obtained have the polymodal shapes being typical of the effects of substances at ultra low doses. Using 16-doxylstearic acid it is detected the increase in the number of thermoinduced structural transitions and appearance of much more high-cooperative ones, as well as the increase in their effective activation energy with the rise of temperature at the supplement of different alpha-tp doses.
authors.affiliation: Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119991 Russia. Belov_V_V@hotmail.com
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; D000975:Antioxidants / Q000494:pharmacology; D003497:Cyclic N-Oxides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000187:drug effects*; D007425:Intracellular Membranes / Q000737:chemistry / Q000187:drug effects*; D008051:Lipid Bilayers / Q000737:chemistry*; D008099:Liver / Q000737:chemistry / Q000166:cytology / Q000187:drug effects*; D008563:Membrane Lipids / Q000737:chemistry; D051379:Mice; D008815:Mice, Inbred Strains; D013113:Spin Labels; D013499:Surface Properties; D013696:Temperature; D014783:Viscosity; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D003497:Cyclic N-Oxides; D008051:Lipid Bilayers; D008563:Membrane Lipids; D013113:Spin Labels; C032363:16-nitroxystearic acid; D024502:alpha-Tocopherol