The influence of the nerve on lower jaw regeneration in the adult newt, Triturus viridescens,


  • Robert A. Finch

    1. Department of Anatomy and Developmental Biology Center, Case Western Reserve University, Cleveland, Ohio
    Current affiliation:
    1. Department of Biology, Brandeis University, Waltham, Massachusetts 02154
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  • Portion of a thesis submitted to the Graduate School of Case Western Reserve University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Anatomy.

  • This investigation was supported by grants GM 08580-07 and GM 12653 from the National Institutes of Health. The work was performed while the author held a pre-doctoral fellowship from the National Institutes of Health.


The present investigation was undertaken in an attempt to determine the role played by the nerve in the regeneration of the lower jaw of the adult newt, Triturus viridescens. The results indicated that the number of nerve fibers normally available at the amputation surface was very low compared with that of the newt forelimb. Furthermore, denervation of the lower jaw reduced the number of nerve fibers available to an extremely low level and maintained the number at a low level for up to four weeks without intervening redenervations. The regenerative events in the denervated and amputated lower jaws were indistinguishable histologically from those in amputated jaws having normal innervation. This presented an apparent exception to the general rule that regeneration of external body parts is dependent on the nerve. Several possible explanations are proposed by which this apparent exception might be explained. The process following amputation might be an exaggerated form of wound healing and tissue regeneration which can occur in the absence of nerves. The tissues of the lower jaw might be more sensitive to the influence of those nerve fibers present. The nerve fibers themselves might be qualitatively different and thus exert a greater influence on the tissues.