Biology of gangliosides: neuritogenic and neuronotrophic properties

Research on the biologic function of gangliosides has accelerated in recent years following discovery of their pronounced effects when administered exogenously to neurons in culture and in vivo. These effects are of two principal types: 1) neuronotrophic, concerned primarily with survival and maintenance of the neuron, and 2) neuritogenic, involving significant increase in the number, length, and/or branching of neuronal processes. Such neurite-promoting activity has been observed in primary cultures of neurons from brain and ganglia as well as transformed lines of neuronal origin. These phenomena may be related to the remarkable growth of aberrant secondary neurites, often accompanied by synaptogenesis, observed in the gangliosidoses. Several in vivo studies have shown exogenously administered gangliosides to aid nervous system repair in both the CNS and PNS, although it is not clear in some cases whether the observed effects should be attributed to neuronotrophic or neuritogenic effects (or both). This article attempts to briefly review the principal developments that have occurred in this area of ganglioside research over the past several years. It also presents for consideration some of the tentative hypotheses put forward concerning mechanism of action.