STRUCTURE AND FUNCTIONS OF LECTINS IN THE CENTRAL AND PERIPHERAL NERVOUS-SYSTEM

There is increasing evidence that lectins are widely distributed in ma mmalian tissues, including the nervous tissue. Based on histochemical techniques using neoglycoproteins, different lectin activities specifi c for different monosaccharides or glycans have been identified (fucos e, galactose, mannose, N-acetylglucosamine, N-acetylgalactosamine, N-a cetylneuraminic acid and heparin). Most of them showed a cellular spec ificity and developmental regulation in the central nervous system. Se veral lectins isolated from the nervous tissue seem to play an essenti al role during ontogenetic processes, especially as far as cell adhesi on and cell recognition mechanisms are concerned (axonal growth and fa sciculation, neuron migration, synaptogenesis, myelination). But some of them seem to be involved in signaling events both intracellularly ( nuclear lectins) or at the cell surface by autocrine and paracrine mec hanisms. This review discusses the structure and the identified functi ons of these important constituents of the nervous tissue.