THE MAINTENANCE OF HIPPOCAMPAL LONG-TERM POTENTIATION IS PARALLELED BY A DOPAMINE-DEPENDENT INCREASE IN GLYCOPROTEIN FUCOSYLATION

Induction of long-term potentiation (LTP) in hippocampal slices of rats caused an increase in both protein synthesis and glycoprotein fucosylation by 38 and 34%, respectively. The enhanced incorporation of [H-3]fucose into glycoproteins observed 1 h after tetanization was abolished in the presence of the dopamine D1 receptor antagonist SCH23390 during stimulation whereas the LTP-induced increase of protein synthesis was not influenced by this drug. The enhanced insertion of [H-3]fucose into hippocampal glycoproteins 1 h after tetanization was paralleled by an increase in the activity of the fucose metabolizing enzyme, fucokinase. In contrast no changes in protein and glycoprotein synthesis were detectable 5 h after tetanization of the slices. The results provide evidence that in addition to an enhanced protein synthesis a dopamine (D1) mediated increase in glycoprotein fucosylation is necessary for the maintenance of the late stage of LTP.