Extracellular matrix: an immunological and biochemical (CAT and TOH activity) survey of in vitro differentiation of isolated amphibian neuroblasts

After neural induction certain cells in the neuroepithelium immediately acquire the property to express certain neural phenotypes (Duprat et al., 1984, 1987). However, the activity of almost all the specific enzymes involved in the biosynthesis of neurotransmitters is considerably higher when neurectodermal cells are cultured with chordamesodermal cells than when they are cultured alone. The stimulating effects of chordamesoderm do not appear to be due to diffusible factors (Duprat et al., 1985b). The present study was designed to investigate the role of extracellular matrix components in neuronal cell differentiation. We showed that the extracellular matrix cannot replace chordamesoderm in stimulating the biochemical differentiation of neuroblasts, although fibronectin and especially laminin stimulate morphological differentiation. We suggest that interaction between neuronal and non-neuronal cells plays an important part in functional biochemical differentiation, whereas the molecules of extracellular matrix are important for morphological differentiation.