Limb regeneration and nerve fiber number in <i>Rana sylvatica</i> and <i>Xenopus laevis</i>

Rzehak, K; Singer, Marcus

doi:10.1002/jez.1401620103

Cited by 37 publications

(2 citation statements)

References 19 publications

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“…'Anuran amphibians can regenerate complete limbs only during the early larval stages, and an insufficient supply of nerves has been put forward as one reason for the decline of the regenerative capacity during larval development and for the inability of postmetamorphic frogs' limbs to regenerate (Singer et al 1957;Rzehak and Singer 1966). However, in a recent work (Filoni and Paglialunga 1990) based on denervation of amputated hindlimbs of J(enopus laevis tadpoles at different stages of development, it has been demonstrated that early limbs can also regenerate after denervation and that nerve-dependence for limb regeneration is established proximo-distally during larval development, as the limb undergoes a process of proximo-distal differentiation.…”

Section: Introductionmentioning

confidence: 99%

Nerve-independent DNA synthesis and mitosis in regenerating hindlimbs of larval Xenopus laevis

Cannata¹,

Bernardini²,

Berardino³

et al. 1992

Roux's Arch Dev Biol

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Xenopus laevis larvae at stage 52-53 (according to Nieuwkoop and Faber 1956) were subjected to amputation of both limbs at the thigh level as well as to repeated denervations of the right limb. Results obtained in larvae sacrificed during wound healing (1 after amputation), blastema formation (3 days) and blastema growth (5 and 7 days) showed that denervated right limbs have undergone the same histological modifications observed in innervated left limbs and have formed a regeneration blastema consisting of mesenchymal cells with a pattern of DNA synthesis and mitosis very similar to that in presence of nerves. Also, the patterns of cellular density in regenerating right and left limbs were very similar. On the whole, the data here reported show a highly remarkable degree of nerve-independence for regeneration in hindlimbs of larval Xenopus laevis at stage 52-53 and lend some substance to the hypothesis that, in early limbs, there would exist trophic factors capable of replacing those released by nerves, promoting DNA synthesis and mitosis in blastemal cells.

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Section: Introductionmentioning

confidence: 99%

Nerve-independent DNA synthesis and mitosis in regenerating hindlimbs of larval Xenopus laevis

Cannata¹,

Bernardini²,

Berardino³

et al. 1992

Roux's Arch Dev Biol

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“…Amphibian limb regeneration is normally dependent upon a threshold level of innervation [7,9,12]. The proposed neurotophic factor which stim ulates regeneration has not been identified but is thought to be of high molecular weight [2,6].…”

Section: Introductionmentioning

confidence: 99%

Inhibition by Acetylcholine of Protein Synthesis in Cultured Limb Regenerates

Foret¹,

Babich²

1973

Oncology

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Cultured amphibian limb blastemas at both early and late stages of regeneration were treated with acetylcholine (ACH). Incorporation of radioactive leucine or thymidine was measured after 24 h. A significant reduction in leucine incorporation was observed in experimental cultures, particularly at the earlier stage of regeneration, whereas DNA synthesis was apparently unaffected. It is suggested that ACH may be involved in the regulation of protein synthesis during regeneration of the newt limb in vivo.

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The relation between the caliber of the axon and the trophic activity of nerves in limb regeneration

1967

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Previous work from this laboratory demonstrated a relation between ability to regenerate a limb and number of nerve fibers available per unit area of amputation wound. Animals with fewer fibers than the newt, Triturus, (for example, Rana, Anolis, and Mus) do not regrow the limb. An exception appeared in Xenopus whose limb is sparsely innervated and yet which regenerates. The present work demonstrates that the nerve fibers of Xenopus make up in individual size what they lack in number. When the average cross-sectional area of the axons was multiplied by the number of fibers per unit area, the results showed that the Xenopus limb is about as well supplied with axoplasm as that of Triturus. This was not true for Rana. The results also demonstrate for the first time a direct relation between caliber and trophic effectiveness of the axon, the evolutionary significance of which is discussed.In previous studies from this laboratory on the dependence of limb regeneration upon the nerve, a direct relation was drawn between the number of nerve fibers available at the amputation surface of the forelimb and the ability of the stump to regrow a new limb (see review, Singer, '52). In the newt, Triturus, the number of nerve fibers normally available per unit area of amputation surface is more than sufficient to cause regrowth. However, if this number is reduced below a critical threshold, by selective destruction of the brachial nerves or nerve roots, regeneration does not ensue. In forms which do not regenerate the limb, for example the frog, Rana, the lizard, Anolis, and the mouse, the number of nerve fibers per unit amputation area is substantially less than that found in the limb of the newt; indeed, it is within or is less than the range of nerve fibers required for regeneration of the newt's limb (Rzehak and Singer, '66, '66a). One of us (Singer, '51. '54, '61) also found for Rana and Anolis that, if the number of nerve fibers in the limb is augmented by deviating an extraneous large nerve into the limb, regeneration occurs presumably because the nerve fiber threshold for limb regeneration is now satisfied (see also Simpson, '61 ; Kudokotsev, '62).An exception appeared to the rule that quantity of innervation is directly related to ability of the limb to regenerate (Rzehak J. EXP. ZOOL., 166: 89-98.and Singer, '66a). We observed that the number of fibers normally available at the amputation of the upper arm is much less in the adult African clawed frog, Xenopus, than in Triturus; and, indeed, substantially less than the threshold number required for regeneration in Triturus (see fig. 2, left). Yet, the limb of Xenopus did regenerate. Initial histological observations on the nerves of Xenopus suggested an answer to this paradox. The peripheral fibers are in general much larger than those of any other form we studied. This being the case, it must follow that the amount of axoplasm per nerve fiber is much greater at the amputation surface in Xenopus than in Triturus. If trophic activity of the axon is directly relate...

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Limb regeneration and nerve fiber number in Rana sylvatica and Xenopus laevis

Cited by 37 publications

References 19 publications

Nerve-independent DNA synthesis and mitosis in regenerating hindlimbs of larval Xenopus laevis

Nerve-independent DNA synthesis and mitosis in regenerating hindlimbs of larval Xenopus laevis

Inhibition by Acetylcholine of Protein Synthesis in Cultured Limb Regenerates

The relation between the caliber of the axon and the trophic activity of nerves in limb regeneration

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