Electron cytochemical study of carbogydrate components of surface membrane in cultured glial cells of the snailHelix pomatia

Abstract

Using a variety of colloidal gold-labelled lectins, the structure and topography of carbohydrate determinants of the surface membrane in different types of cultured glial cells of the snailHelix pomatia have been electron cytochemically investigated. Analysis of lectin binding having different sugar specificities have shown heterogeneity of carbohydrate pools between glial and nerve cells and among different types of glial cells. It was found that satellite glial cells displaying ultrastructural traits of intensive metabolism (type II cells) selectively bindGNA, which is specific for terminal α-D-mannose residues, and do not interact (Con A) or slightly interact (LCA) with other mannose-specific lectins.GNA determinants remain during the whole period of cell growth and are absent in satellite type-I glial cells, fibrous glial cells, microglia, and neurons.LTA, PVA, andLABA do not bind to any glial cells.WGA determinants, which are abundant on the neurons, are completely absent onGNA-binding glial cells and single on other types of glial cells. The density ofPNA determinants on microglial cells is the highest, as compared with other types of glial cells or neurons. It is concluded that some lectin determinants (forRCA-1, PNA, LPA) are present on all types of glial cells, while another determinant (GNA) is specific for a certain type of glial cells only and can serve as a marker of these cells. The role of specific carbohydrate determinants for neuron-glia interaction in mature brain is discussed.