CARBOHYDRATES PLAY A ROLE IN NEURITE OUTGROWTH IN-VIVO DURING DEVELOPMENT AND REGENERATION

We have used the alpha-glucosidase inhibitor, castanospermine, to inve stigate the possible involvement of N-linked glycosylation in the proc ess of neurite outgrowth both during the development and regeneration of sympathetic nerve fibres into the iris of the rat. The effects on n erve growth were assessed qualitatively using catecholamine histochemi stry and quantitatively by measuring the uptake of [H-3]noradrenaline. Castanospermine was injected during the first, second or third postna tal week or during the second to fourth week after degeneration of adr energic nerve terminals with the neurotoxin, 6-hydroxydopamine, Result s showed that both the initial growth of sympathetic nerve fibres, as well as the regeneration of these fibres, was inhibited by castanosper mine treatment. The inhibitory effects were restricted to injection of castanospermine at particular time periods during postnatal developme nt and regeneration. These results suggest that N-linked carbohydrates may be important in particular stages of the processes of initial ner ve growth and regeneration of sympathetic nerve fibres in the iris.