ADAPTATION TO ETHANOL-INDUCED FLUIDIZATION OF BRAIN LIPID BILAYERS

We have shown that ethanol is less able to fluidize reconstituted membranes prepared from lipid extracts of tolerant mice synaptosomal membranes than those prepared from controls. The effects of ethanol on membrane fluidity were assessed by fluorescence polarization technique. Acute in vivo administration of ethanol did not alter ethanol-induced fluidization of the bilayers. These results suggest that changes in the lipid composition of membranes can account, at least in part, for tissue adaptation to ethanolinduced membrane fluidization. We also discuss the use of reconstituted membranes as a tool both to analyze the significance of changes in membrane composition for the development of tolerance and to refine our concepts concerning the relation between membrane fluidity and anesthetic activity. © 1979.