Effects of chronic consumption of ethanol and low-thiamin, low-protein diets on the lipid composition of rat whole brain and brain membranes.

Four groups of rats were used in a nutritionally-controlled study of effects of chronic ethanol consumption on brain membrane lipid composition. Rats chronically consuming ethanol were fed high-nutrient or low-thiamin, low-protein diets. After 4 months, lipid analyses were performed on brains, brain microsomes and myelin from each group and from pair-fed, non-ethanol controls. Among the effects of ethanol was an increase of the relative proportion of cholesterol in microsomal lipids while there was decrease of it in myelin. Ethanol also increased plasmenylethanolamine while decreasing phosphatidylethanolamine proportions in myelin and in whole brain lipids, decreased the total lipid phosphorus of whole brain, and elevated the proportion of phosphatidylserine in microsomal and whole brain lipids. Effects of poor diet generally did not interfere with ethanol effects except in the case of microsomal lipids, where it apparently prevented an ethanol-induced increase in proportion of cholesterol. These changes may be adaptive responses to the fluidizing effect of ethanol on membranes.