Different effects of 2-deoxy-sugars on memory formation.

When rats were trained on a brightness discrimination task, intrahippocampal injections of 2-deoxy-galactose interfered with long-term memory formation while galactose and 2-deoxy-glucose were ineffective altogether. No differences were found in the morphology of hippocampal CA1 neurons investigated light-microscopically after application of the sugars. The amnestic action of 2-deoxy-galactose is discussed in the light of a rather specific interference with fucosylation of proteoglycans involved in mechanisms underlying the formation of a memory trace.