The growth of segmental nerves from the spinal cord to the hind limb-bud in the axolotl.
It has been concluded from previous experiments involving the growth of segmental nerves from the amphibian spinal cord to the limb-bud that axons are attracted to the limb-bud region by their target tissue (Hamburger, 1929; Hughes and Tschumi, 1958). In the present study this hypothesis has been tested by obstructing the pathways over which the nerves normally grow. It was found that for those nerves which marginally obstructed far fewer axons were able to reach their target. The spinal ganglia associated with these nerves contained up to 50% fewer cells than the adjacent unobstructed segmental level. These results suggest that nerves are not attracted from the spinal cord by the target tissue, but rather that the pathways provided by the axial segmental nerves are essential if a normal number of axons are to reach their target.
D000558:Ambystoma mexicanum; D000818:Animals; D005727:Ganglia, Spinal / Q000166:cytology; D006614:Hindlimb / Q000294:innervation*; D009420:Nervous System / Q000254:growth & development*; D013116:Spinal Cord / Q000033:anatomy & histology*