Regeneration of reversed aneurogenic arms of the axolotl.
Aneurogenic arms of young axolotls were implanted into the flank as heterotopic autografts with reversed proximo-distal orientation. The formerly proximal ends of such arms regressed to a variable extent, and then either regenerated or could do so following a second amputation. The regenerate always contained a complete sequence of skeletal elements between the adjacent stump skeleton and terminal digits, being a mirror image of the implanted arms with identical transverse axes but an opposed proximo-distal axis. Many reversed arms also regenerated fingers from the implanted hand. Identical results were obtained from reversed arms of control larvae, confirming previous studies on reversed well-innervated arms. Nerves are not required for the establishment of a new proximo-distal axis, therefore, and probably have no influence on the determination of any limb axis. Morphogenesis of the regenerate is clearly related to the position along the proximo-distal axis where the blastema originates. Although this axis is reasonably envisaged in terms of a gradient, its polarity is ignored during regeneration.
D000557:Ambystoma / Q000502:physiology*; D000818:Animals; D003714:Denervation; D005552:Forelimb / Q000294:innervation / Q000502:physiology* / Q000637:transplantation; D009024:Morphogenesis; D010227:Parabiosis; D012038:Regeneration; D012399:Rotation; D014182:Transplantation, Autologous