Neurite extension after damage by laser beam irradiation in cultured chick sensory neurons.

We studied the effects of neurotrophic factors on neurite extension and branching of embryonic chick sensory neurons in culture after damage to their filopodia by an irradiating laser beam. The factors employed were nerve growth factor (NGF), basic fibroblast growth factor (bFGF), ganglioside GM1 (GM1), laminin (LAM), and combinations of bFGF plus NGF, and LAM plus NGF. Neither NGF, bFGF, nor NGF plus bFGF affected either the neurite extension or the amount of branching of damaged and intact neurites. Ten micrograms/ml of GM1 tended to enhance the extension of damaged neurites. One hundred micrograms/ml of LAM significantly enhanced the elongation of damaged neurites but not intact ones. One hundred micrograms/ml of LAM with 10 ng/ml of NGF significantly elongated the neurite lengths of both damaged and intact neurites. These results suggest that LAM plays an important role in neurite extension after damage to peripheral sensory neurons and that NGF modulates the effect of LAM.