MOVEMENT OF EMBRYONIC CHICK SYMPATHETIC NEURONS ON LAMININ IN-VITRO IS PRECEDED BY NEURITE EXTENSION

Chick sympathetic neurons (E-9) are capable of moving on a laminin substrate but not on more adhesive substrates in vitro. The effect of laminin is dose-dependent and reduced by the addition of anti-laminin antibodies, whereas soluble laminin does not stimulate movement. The onset of neuronal movement is preceded by, and highly correlated with, the onset of neurite formation. The addition of 1,2 dioctanoyl-sn-glycerol (DAG), a stimulator or protein kinase C that has been shown to inhibit neurite outgrowth, was found to delay both process formation and neuronal movement but did not affect the correlation between these two measures. These results support the conclusion that laminin stimulates primary neuronal movement in vitro and suggest that the mechanism underlying movement involves process formation followed by ''towing'' of the cell body by the advancing process. The similarities of this in vitro behavior to that observed in vivo suggest that similar mechanisms may underlie neuronal movement in the developing nervous system as suggested by Morest (Z Anat Entwicklungsgesch 130:265-305, 1970) and Liesi (EMBO J 4:1163-1170, 1985; Exp Neurol 117:103-113, 1992). (C) 1993 Wiley-Liss, Inc.