Effects of dimyristoylphosphatidylethanol and ethanol on thickness of neuronal membrane lipid bilayers

Abstract

The aim of this study was to provide a basis for examining the molecular mechanism for the pharmacological action of ethanol. Energy transfer between the surface fluorescent probe 1-anilinonaphthalene-8-sulfonic acid and hydrophobic fluorescent probe 1,3-di(1-pyrenyl)propane was used to examine the effect of both dimyristoylphosphatidylethanol (DMPEt) and ethanol on the thickness (D) of the synaptosomal plasma membrane vesicles (SPMV) isolated from the bovine cerebral cortex. The thickness (D) of the intact SPMV was 1.044 +/- 0.008 (arbitrary units, n=5) at 37 degrees C (pH 7.4). Both DMPEt and ethanol decreased the thickness of the SPMV lipid bilayer in a dose-dependent manner with a significant decrease in thickness observed at 5 microM and 25 mM, respectively. It was assumed that both ethanol and DMPEt cause interdigitation in the SPMV lipid bilayers. The effects of ethanol on the neuronal membranes were attributed to its direct and indirect actions. The indirect action of ethanol refers to the action of phosphatidylethanol, which is an ethanol abnormal metabolite, on the neuronal membranes. The decrease in membrane thickness by both DMPEt and ethanol might be responsible for some, but not all of its anesthetic actions.

Trolox reduces the effect of ethanol on acetylcholine-induced contractions and oxidative stress in the isolated rabbit duodenum

“…In the current study, ethanol decreased ACh-induced contractions in rabbit duodenum and this accords with other studies in which ethanol has been shown to reduce the contractions produced by ACh in isolated rat ileum (32), in canine jejunal circular smooth muscle (8) and in rabbit duodenum (13). Furthermore, ethanol decreased the thickness of synaptosomal plasma membrane vesicles lipid bilayer (33).…”

Estudo dos efeitos das serinoproteinases PA-BJ e Giroxinas isoladas de venenos de serpentes em cultura de células endoteliais

“…Uma provável explicação para este fato seria a capacidade demonstrada do DMSO induzir a translocação de moléculas de lipídeos e sua re-distribuição entre as faces externa e interna da membrana celular, em evento conhecido como flip-flop, causando uma diminuição da espessura da membrana celular e mudança na carga iônica dos lipídeos da superfície da mesma (GURTOVENKO et al, 2008). De modo similar, dados da literatura demonstraram que o etanol causa uma diminuição na espessura da membrana celular, também, por alterações na posição dos lipídeos na bicamada dessas membranas (PARK et al, 2009). A partir dessas informações, podemos sugerir que a posição e/ou as cargas iônicas dos lipídeos de superfície da membrana celular seja um aspecto importante para a interação da PA-BJ com as CEs e, conseqüentemente, para o desencadeamento de sua ação sobre as mesmas.…”