A Quantitative Study of Innervation in Newt Multiple Limbs: Nerve Fibre Counts in Multiple Limbs Produced from Either Limb Buds or Mature Regenerating Limbs
Multiple limbs were obtained from either limb buds or mature limbs. By counting the fibers of the main nerves at homologous levels of both multiple limbs and contralateral single limbs, it was shown that the innervation of each duplicated distal part of the limb was quantitatively similar to the innervation of an equal single limb. Only in the late induced multiple limbs from regenerating mature limbs, the excess of nerve fibers distal to the branching level of the multiple limbs, modified a little if any the fiber amount of the proximal common base. In the early induced multiple limbs from limb buds, a large percentage of the distal fiber excess was found in the nerves of the common base of the limb. These results suggest a possible additional recruitment of neurons only at an early stage of limb formation. They are discussed in connection with results obtained in other vertebrates.
KeywordsNerve Fiber Single Limb Neuron Pool Main Nerve Ventral Ramus
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