The influence of local anesthetics on molecular organization in phosphatidylethanolamine membranes.

摘要: The influence of the local anesthetics tetracaine (TTC) and procaine (PRC) on bilayers specifically deuterated phosphatidylethanolamines (PE) has been studied by 2H 31P NMR. Dimyristoylphosphatidylethanolamines (DMPE), at positions 2, 4, 14 sn-2 chain, position 2 sn-1 in ethanolamine headgroup, were mixed 1:1 with a semisynthetic egg PE effect measured quantities TTC PRC quadrupole splittings, spin-lattice relaxation times, chemical shift anisotropy observed. Experiments performed pH 5.5, when are primarily charged, 9.5, they uncharged. Tetracaine was observed to disorder hydrocarbon region bilayer induce conformational change headgroup. Conversely, had little or no induced only small These changes disordering effects, adjusted for anesthetic partitioning, essentially independent charge anesthetic. However, 5.5 low TTC/PE molar ratios (less than 0.1), NMR spectra showed two lipid environments--one corresponding free other contact TTC. Continued addition resulted eventual disappearance signal growth from At is uncharged, one This indicates that pH, it much slower rate lateral diffusion bilayer. In mixtures phosphatidylserine, headgroup noted which similar seen pure PE; however, there evidence slow anesthetics. effects bilayer, combined our earlier study labeled [Kelusky, E.C., I.C.P. Smith, Biochemistry, 22:6011-6017 (1983)], indicate penetrates into portion whereas sites region.