Abstract
Polysialic acid (PSA) is a large carbohydrate added post-translationally to the extracellular domain of the Neural Cell Adhesion Molecule (NCAM) that influences its adhesive and other functional properties. PSA-NCAM is widely distributed in the developing nervous system where it promotes dynamic cell interactions, like those responsible for axonal growth, terminal sprouting and target innervation. Its expression becomes restricted in the adult nervous system where it is thought to contribute to various forms of neuronal and glial plasticity. We here review evidence, obtained mainly from hypothalamic neuroendocrine centers and the olfactory system, that it intervenes in structural synaptic plasticity and accompanying neuronal-glial transformations, making possible the formation and elimination of synapses that occur under particular physiological conditions.
Acknowledgements
This work was partially supported by grants from the Compagnia di San Paolo (Progetto NEUROTRANSPLANT 2004.2019 and 1553 IT/CV), Regione Piemonte (CIPE 2004-A14), M.U.R.S.T. (PRIN), University of Turin (to L.B.) and Inserm (to D.T.T.).