Journal of Neuroscience, Vol 6, 2019-2025, Copyright © 1986 by Society for Neuroscience
Effects of nerve growth factor on differentiation of muscle spindles following nerve lesion in neonatal rats
S Sekiya, S Homma, Y Miyata and M Kuno
Central synaptic function of Group Ia sensory fibers has been shown to be
enhanced by daily applications of NGF in neonatal rats. In the periphery,
Group Ia sensory fibers are known to trigger the differentiation of muscle
spindles. In the present study we examined, in neonatal rats, whether daily
NGF treatment affects the number or structure of spindles formed in muscle
whose nerve has been crushed. The results show that 25-35 d after nerve
crush, de novo supernumerary spindles were formed by treatment with NGF in
the temporarily denervated muscle. The number of spindles in the
corresponding muscle on the contralateral, intact side was not affected by
NGF treatment. Following nerve crush alone, the mean number of spindles in
the muscle was not significantly different from the normal value. It is
suggested that treatment of neonatal rats with NGF may facilitate the
outgrowth of excessive peripheral collaterals of regenerating Group Ia
sensory fibers, which, in turn, contributes to the formation of de novo
spindles as a result of interaction with myotubes.