Brain glycoconjugates in alcohol and narcotic research

The glycoconjugates may be divided into three major groups: glycolipids, glycosaminoglycans and glycoproteins. The brain contains a considerable amount of glycolipid and smaller but appreciable amounts of glycoproteins and glycosaminoglycans. The alterations of the brain glucoconjugates found in conditions which affect brain function have not been extensively studied. Alcohol intoxication has been reported to increase the ganglioside content of rat brain. On the other hand lowered gangliosides and glycoproteins have been noted in brain tissue of a human alcoholic. The sialic acid levels associated with gangliosides and with glycoproteins both decreased in morphine dependent rats after withdrawal of the drug. Chronic administration of lithium increased the amount of hyaluronic acid in the cerebellum of rats, but did not affect the chondroitin sulfate level. Further investigation of the glycoconjugates as affected by alcohol and other drug abuse may provide explanations for some of the changes in brain function in these conditions.