POLYSIALYLATION AS A REGULATOR OF NEURAL PLASTICITY IN RODENT LEARNING AND AGING

Although generally accepted to play an important role in development, the precise functional significance of NCAM remains to be elucidated. Correlative and interventive studies suggest a role for polysialylated NCAM in neurite elaboration. In the adult NCAM polysialylation contin ues to be expressed in regions of the central nervous system which ret ain neuroplastic potential. During memory formation modulation of poly sialylation on the synapse-enriched isoform of NCAM occurs in the hipp ocampus. The polysialylated neurons of this structure have been locate d at the border of the granule cell layer and hilar region of the dent ate and their number increases dramatically during memory consolidatio n. The converse is also true for a profound decline in the basal numbe r of polysialylated neurons occurs with ageing when neural plasticity becomes attenuated. In conclusion, it is suggested that NCAM polysialy lation regulates ultrastructural plasticity associated with synaptic e laboration.