Ganglioside Effects on Astroglial Cells in Vitro

Abstract

It is increasingly recognized that neuronal maintenance, function and repair capabilities may depend in vivo — as they do in vitro — on the availability to the neuron of appropriate extrinsic agents. Three classes of such agents have already been recognized (Varon and Adler, 1980; 1981; Varon et al., 1984; Varon, 1985). Neuronotrophic agents are presumed to control neuronal survival and general capabilities for growth and/or function. Neurite promoting agents are specifically involved in modulating the execution of neuritic programs, i.e. the extension of axons and dendrites. Transmitter modulating agents are concerned with the choice of transmitter modalities expressed by a nerve cell. As research in this field proceeds, it will become possible to specify additional categories of neuronoactive, extrinsic agents. In vivo, as in vitro, extrinsic neuronoactive agents may occur i) free in the humoral environment (extracellular fluid, culture media), ii) anchored to interstitial structures (extracellular matrices, culture substrata), and/or iii) on the surfaces of other cells with which neurons come into contact.