Inhibition of Proteolytic Activity as Modulation of Neurite Outgrowth

Abstract

Glial cells, including glioma cells, grown in tissue culture release macromolecular factors which can promote neurite extension and/or survival of neuronal cells[1,2]. One of these factors induces neurite extension in neuroblastoma cells[1]. A similar neurite promoting activity is also found in the medium conditioned by rat brain primary cultures[3]. In such media, there is a correlation between the presence of the biological activity and the age of the animal from which the primary culture was derived[3]. This sharp rise in neurite promoting activity released by brain primary cultures derived from 3–5 days old animals coincides with the period of rat brain development at which the burst of glial cell multiplication takes place. Since neural arborization strongly expands at, or just following this phase, these results have suggested the relevance of such an glia-derived activity in postnatal rat brain maturation. They also revealed the existence of a type of molecular mediators in glia-neuronal interactions.