Interaction of soluble and substratum-bound factors influences neurite elongation.

Neurite elongation was investigated in explanted chick dorsal root ganglia (DRG) using either serum-supplemented or defined N1 medium and different culture substrata. The results indicate that there is no substantial difference in neurite elongation on the three substrata when ganglia are grown in N1 medium. In contrast, neurite length depends on the substratum in serum-supplemented medium and in general exceeds that obtained in N1 medium. Optimal neurite growth was observed in N1 medium when culture dishes have been precoated with serum. Our data suggest that while soluble serum molecules inhibit neurite growth adsorbed serum constituents clearly stimulate neurite elongation.