Kurabuchi S
Department of Histology, School of Dentistry, Nippon Dental University, Tokyo, Japan.
Int J Dev Biol. 1992 Sep;36(3):429-33.
The limb regenerative capacity and the quantity of innervation (the percentage of a cross-sectional area of amputation forelimb stump occupied by nerves) in the pond frog, Rana brevipoda porosa, was investigated in postmetamorphic froglets and adults of various sizes by means of amputating forelimbs through the zeugopodium. Nearly all the amputated limbs of newly metamorphosed froglets, 18-19 mm in snout-vent length, showed heteromorphic regeneration. However, the larger the body size, the lower the presence of limb regeneration. Limb regenerative capacity was completely lost in froglets and adults with snout-vents larger than 35 mm. The quantity of innervation of limbs was highest in newly metamorphosed froglets, gradually decreasing with growth. The nerve quantity in adults with a snout-vent length between 60-67 mm was approximately half that of the froglets. When the nerve supply was augmented by deviating ipsilateral sciatic nerve bundles to the forelimb stump, almost all limbs, which were usually non-regenerative with normal innervation, regenerated heteromorphically. These results show that the decline in limb regenerative capacity during postmetamorphic growth is in part attributable to the reduction in innervation levels to below the threshold level required for regeneration.
通过在前肢的zeugopodium处截肢，研究了日本林蛙（Rana brevipoda porosa）幼蛙和成体不同大小阶段的肢体再生能力和神经支配量（截肢前肢残端横截面积中神经所占的百分比）。几乎所有刚变态的幼蛙（吻肛长度为18 - 19毫米）截肢后的肢体都表现出异形再生。然而，体型越大，肢体再生的比例越低。吻肛长度大于35毫米的幼蛙和成体完全丧失了肢体再生能力。肢体的神经支配量在刚变态的幼蛙中最高，并随着生长逐渐减少。吻肛长度在60 - 67毫米之间的成体的神经量约为幼蛙的一半。当通过将同侧坐骨神经束转移到前肢残端来增加神经供应时，几乎所有通常在正常神经支配下不能再生的肢体都发生了异形再生。这些结果表明，变态后生长过程中肢体再生能力的下降部分归因于神经支配水平降低到再生所需的阈值水平以下。
