Cell-substratum adhesion of neurite growth cones, and its role in neurite elongation.

The adhesion of chick embryo sensory neurons to glass coverslips was examined with interference reflection optics. On untreated glass, adhesive contacts are common only beneath growth cones and are small. On polylysine-treated glass growth cones are highly spread, microspikes reach treat lengths and extensive adhesive contacts underlie growth cones, microspikes and nerve fibers. Veils, expanded from the growth cone, are adherent to the substratum either centrally or laterally, while the extending edge of the cell margin is non-adherent. Linear adhesions are frequent beneath microspikes and pass centrally beneath the growth cone margin. The distribution of linear adhesions resembles that of microfilament bundles seen within whole mounts of growth cones. Adhesive contacts stabilize extensions of the growth cone margin and may influence the organization of the microfilamentous network within the growth cone. Regulation of microfilament organization by adhesion may influence microfilament functions in growth cone mobility and the assembly of neurite structures.