MIGRATORY CELL LOCOMOTION VERSUS NERVE AXON ELONGATION : Differences Based on the Effects of Lanthanum Ion

The effects of lanthanum ions (La⁺⁺⁺) on the locomotion and adhesion of g lial cells and elongating nerve axons are reported. La⁺⁺⁺ increases adhesion of both glia and of nerve growth cones to a plastic substratum. La⁺⁺⁺ also markedly reduces glia locomotion, but it does not inhibit nerve elongation. Electron-opaque deposits are seen on the cell surface and within cytoplasmic vesicles of glia and nerves cultured in a La⁺⁺⁺-containing medium. Possible modes of action for La⁺⁺⁺ are discussed, particularly the possibilities that Ca⁺⁺ fluxes or Ca⁺⁺ involvement in adhesion are altered by La⁺⁺⁺. The results are consistent with the hypothesis that cell migration and nerve axon elongation differ in mechanism, with respect to both adhesive interactions and the activity of microfilament systems.