AMPHIBIAN
LIMB
REGENERATION
CHARLES S. THORNTON
1
Department
oj Zoology, Michigan State University, East Lansing,
Michigan
I. Introduction
205
II. Phases of Limb Regeneration
207
A. Regressive Phase
207
B. Progressive Phase
220
III. The Influence of Nerves on Limb Regeneration
231
IV. The Influence of Hormones on Limb Regeneration
236
V. Discussion and Conclusions
' .
242
References
244
I. Introduction
Regeneration is usually defined as the sequence of morphogenetic
activities which restore the normal structure of an organism following the
loss of part or parts of it. As Needham (1960) has argued, "regenesis" is
perhaps a more precise word for this phenomenon since it implies morphogenetic restoration of organs originally developed ontogenetically. Child
(1941), who preferred the term "reconstitution," defined the process
"as the alteration of pattern and course of development in a part of a
pre-existing individual following its physical or physiological isolation
from its normal organismic environment" (p. 28). He distinguished three
types of reconstitution: (a) substitution, which is particularly common
in plants and involves, in multiaxiate forms (i.e., a conifer), substitution
of another axis for one removed; (b) redifferentiation, which involves
remodeling of remaining tissues to replace a lost part so that there need
be no outgrowth of new tissue; and (c) regeneration, which involves
replacement of lost parts by outgrowth of new tissue from the cut
1
The original work from the author's laboratory has been supported by grants
from the National Institutes of Health (NB 04128) and the National Science
Foundation (GB 2618). Participants in this work, and their support, have been:
Mary Thornton, NIH Research Assistant; Thomas Sprague and John DeFazio,
NIH Graduate Trainees in Developmental Biology; Nicholas Shuraleff, II, NIH
Predoctoral Fellow; Lester Hearson, NSF Science Faculty Fellow; Roy Tassava,
NDEA Predoctoral Fellow; Thomas Connelly and Stephen Purdy, NIH Graduate
Research Assistants.
205
LIMB
REGENERATION
CHARLES S. THORNTON
1
Department
oj Zoology, Michigan State University, East Lansing,
Michigan
I. Introduction
205
II. Phases of Limb Regeneration
207
A. Regressive Phase
207
B. Progressive Phase
220
III. The Influence of Nerves on Limb Regeneration
231
IV. The Influence of Hormones on Limb Regeneration
236
V. Discussion and Conclusions
' .
242
References
244
I. Introduction
Regeneration is usually defined as the sequence of morphogenetic
activities which restore the normal structure of an organism following the
loss of part or parts of it. As Needham (1960) has argued, "regenesis" is
perhaps a more precise word for this phenomenon since it implies morphogenetic restoration of organs originally developed ontogenetically. Child
(1941), who preferred the term "reconstitution," defined the process
"as the alteration of pattern and course of development in a part of a
pre-existing individual following its physical or physiological isolation
from its normal organismic environment" (p. 28). He distinguished three
types of reconstitution: (a) substitution, which is particularly common
in plants and involves, in multiaxiate forms (i.e., a conifer), substitution
of another axis for one removed; (b) redifferentiation, which involves
remodeling of remaining tissues to replace a lost part so that there need
be no outgrowth of new tissue; and (c) regeneration, which involves
replacement of lost parts by outgrowth of new tissue from the cut
1
The original work from the author's laboratory has been supported by grants
from the National Institutes of Health (NB 04128) and the National Science
Foundation (GB 2618). Participants in this work, and their support, have been:
Mary Thornton, NIH Research Assistant; Thomas Sprague and John DeFazio,
NIH Graduate Trainees in Developmental Biology; Nicholas Shuraleff, II, NIH
Predoctoral Fellow; Lester Hearson, NSF Science Faculty Fellow; Roy Tassava,
NDEA Predoctoral Fellow; Thomas Connelly and Stephen Purdy, NIH Graduate
Research Assistants.
205