Content and turnover of gangliosides in rat brain following behavioural stimulation.

— Rats were placed in a tank of deep water to swim until they learned to escape (Group E) or were lifted out (Group F). Controls (Group C) were left in their home cages. Specific radioactivities of purified gangliosides, other glycolipids and nonlipid carbohydrates were measured at 9 and 24 h after intracranial injection of D-[1-14C]glucosamine and the subsequent swimming trials. Nonspecific effects of behavioural stimulation (similar changes in Groups E and F) included decreased net incorporation of radioactivity into monosialogangliosides and nonganglioside carbohydrates, a relative increase in content of GT1 gangliosides and decreased content of GT1 gangliosides. Specific effects (different changes in Groupe E and F) included in Group E decreased net uptake of radioactivity into disialogangliosides. These results demonstrate that in rat brain: (1) ganglioside metabolism is affected by behavioural stimulation; (2) metabolism of other heteropolysaccharides is also affected; and (3) some biochemical changes are consequences of nonspecific stimulation whereas others are associated with specific elements of experience.