The effect of nerve growth factor on limb regeneration in <i>Ambystoma</i>
Abstract
Abstract Young Ambystoma larvae were subjected to forelimb amputation followed by a series of injections of either nerve growth factor (NGF) or saline solution. The animals receiving the NGF injections showed an increase in the length of the regenerate and an acceleration of digit formation at times up to two weeks after amputation. The maximum per cent increase in length occurred at about nine days post‐amputation. By two weeks after amputation, however, the difference between NGF‐treated and control animals had diminished considerably. The nerve growth factor, by increasing the extent of sensory innervation to the stump apparently accelerated blastema formation and early stages of regeneration. The fact that the regenerative rate can be altered by changing the nerve supply implies that there is not an absolute neural threshold for regeneration. Striking differences were noted in the normal regenerative rate of A. opacum as compared with A. maculatum .