Newt forelimb cartilage regeneration after partial denervation



Weekly operations to remove the fourth spinal nerve and prevent its contribution to the neutrotrophic factor available at the amputation stump of the newt arm resulted in significantly smaller regenerates with significant skeletal deficiencies in all four digits when compared to the unoperated control regenerate arm. The fourth nerve deficient arms had more than twice as many gross malformations as did the controls. These effects of partial denervation give tentative support to an hypothesis of neurotome subtraction that suggests a decisive role for nerves in determination of limb tissue.