[Mechanisms of serotonin participation in the consolidation of temporary connections]

The effect of serotonin (5-OT) surplus on incorporation of labelled 14C-leucine and 3H-fucose in the hippocampal proteins was studied in experiments in vivo and in vitro. It was found that intrahippocampal administration of 5-OT in a dose of 5 mcg immediately after elaboration of defensive conditioned reflexes in V-shaped maze impaired the retention of these reflexes and lowered the incorporation of 14C-leucine in the hippocampal proteins. Doubled dose of 5-OT did not cause amnesia and did not change the protein synthesis. In experiments in vitro 5-OT decreased 14C-leucine incorporation and increased 3H-fucose incorporation in total proteins of hippocampal section. The changes in labelled leucine incorporation were in a non-linear dependence on 5-OT concentration. Similar but less pronounced changes in the protein synthesis were also found on sections of the hippocampus taken from animals with a life-time 5-OT surplus. The obtained data confirm the assumption that 5-OT participates in consolidation processes through its controlling effect on protein metabolism.