Journal of Neuroscience, Vol 7, 1857-1865, Copyright © 1987 by Society for Neuroscience
Selective reinnervation of transplanted muscles by their original motoneurons in the axolotl
DJ Wigston and PR Kennedy
The motoneurons innervating 3 hindlimb extensor muscles, anterior and
posterior iliotibialis and iliofibularis, were studied separately by
retrograde labeling with HRP. The motor pools for these 3 muscles
overlapped to such an extent that individual motoneurons between ventral
roots 16 and 17 could not be assigned unambiguously to one pool or another.
Thus, conventional retrograde labeling could not identify particular
axolotl motoneurons. Instead, a double retrograde-labeling technique was
employed to mark the motoneurons innervating a particular muscle, the left
posterior iliotibialis. Either diamidino yellow (DY) or HRP satisfactorily
labeled axolotl motoneurons for at least 3 months in vivo. After labeling,
both anterior and posterior iliotibialis muscles were removed from the
injected limb and replaced with their counterparts from the opposite limb,
in reversed anterior-posterior orientation. Several weeks later, a second
marker (DY or HRP) injected into the posterior iliotibialis muscle in its
new, more anterior, position labeled the neurons that reinnervated this
muscle; the number of neurons labeled with both first and second tracers
gave an indication of the selectivity of reinnervation. Using this
approach, we have found that the majority of neurons reinnervating a
particular muscle are members of that muscle's original motor pool.