The Journal of Neuroscience, December 1, 1999, 19(23):10390-10396
Glial Cells Promote Muscle Reinnervation by Responding to
Activity-Dependent Postsynaptic Signals
Flora M.
Love and
Wesley J.
Thompson
Section of Neurobiology, School of Biological Sciences, Institute
for Neuroscience and Institute for Cell and Molecular Biology,
University of Texas at Austin, Austin, Texas 78712
After nerve injury, denervated synaptic sites in skeletal muscle
commonly become reinnervated by sprouts that grow from nerve terminals
on nearby muscle fibers. These terminal sprouts grow along a glial cell
guide or "bridge" formed by Schwann cell (SC) processes that extend
from denervated synaptic sites. Data presented here show that most
bridges connect innervated and denervated synaptic sites rather than
pairs of denervated sites even when most sites in the muscle are
denervated. Furthermore, bridges are inhibited by presynaptic or
postsynaptic blockade of synaptic transmission, manipulations that do
not alter the extent of SC growth. These results show that an
activity-dependent postsynaptic signal promotes the formation and/or
maintenance of glial bridges and thus muscle reinnervation.
Key words:
reinnervation; Schwann cells; glia; neuromuscular
junction; activity-dependent; postsynaptic
Copyright © 1999 Society for Neuroscience 0270-6474/99/192310390-07$05.00/0