Abnormal fluidity and surface carbohydrate content of the erythrocyte membrane in alcoholic patients

Erythrocyte membranes from 11 healthy individuals and 11 alcoholic patients, examined within 24 hr of withdrawal, were studied for membrane fluidity as assessed by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene and for the concentrations of sialic acid and galactose in the membrane surface. Basal fluorescence polarization was significantly higher in the alcoholics and the membranes were clearly more resistant to the fluidizing effect of ethanol added in vitro. The concentrations of sialic acid as well as galactose were significantly reduced in the patients. The increased resistance to the fluidizing effect of ethanol added in vitro appeared to be functionally related to reduced concentrations of terminal sialic acid and terminal and sialic acid-bound beta-galactose in the membrane surface. The increased basal rigidity is probably due to concomitant changes in the lipid bilayer of the membrane. The results also showed, for the first time, that similar perturbations of membrane fluidity occur in human alcoholics as have been found previously in chronically ethanol-treated animals.