THE ROLE OF CHEMOTAXIS IN MORPHOLOGICAL-DIFFERENTIATION OF MOLLUSK NEURONS

Participation oi chemotaxis in regulation oi morphological differentia tion of neurons has been studied on the culture oi isolated neurons of molluscs by counting the number and determining the length of growing neurites and by changing the cultivation conditions. Morphometric gro wth coefficient C-g has been introduced for estimation of elongation a nd branching of processes. It has been shown that C-g essentially depe nds upon such intracellular secondary mediators as cAMP, cGMP, protein kinase C, Ca2+, H+, which confirms the possibility oi chemotactic reg ulation of the process. On the other hand, the neurites were found to be actively formed in single neurons in the salt solution in individua l chambers when any target cells and chemoattractants were absent. The se data suggest that in some casts (or at certain stages of formation of cellular processes) chemotactic signalling rather associates than d etermines the directional growth of neuronal processes to their target s. The possibility of self-regulation by the autocrine type is not exc epted as well.