Pollack E D, Maheras-Rarick H M
Institute for the Study of Developmental Disabilities, University of Illinois, Illinois 60680.
J Exp Zool. 1990 Jun;254(3):276-85. doi: 10.1002/jez.1402540306.
Developmental manipulations that can alter nerve-limb relationships can assist in understanding the neural control of limb regeneration. Pressure-induced triploidy in Rana pipiens tadpoles results in alterations of the quantitative characteristics of the spinal motor neurons that innervate the limbs, whereas the limbs appear unaltered. Unilateral midthigh amputations at larval stages IX, XI, and XIII of diploid and triploid animals resulted in complete regeneration for only stage IX animals regardless of ploidy. Nevertheless, triploid limbs regenerated much faster than did diploids, an event that can be related to the differential dynamics of nerve fiber extension and/or the altered numbers and sizes of triploid spinal motor neurons. Although normal limb development from stage IX to the endpoint at stage XVIII was the same in diploids and triploids, the rate of regeneration in triploids was nearly twice that of diploids. The data of this noninvasive means of altering the quantitative relationship of nerve-to-peripheral target suggest a unique means of studying nerve-dependent limb regeneration in an animal that progressively loses its regenerative capability during development.
能够改变神经与肢体关系的发育操作有助于理解肢体再生的神经控制。在牛蛙蝌蚪中，压力诱导的三倍体导致支配肢体的脊髓运动神经元数量特征发生改变，而肢体外观未变。在二倍体和三倍体动物的幼虫期IX、XI和XIII进行单侧大腿中部截肢，结果仅IX期动物无论倍性如何均能完全再生。然而，三倍体肢体的再生速度比二倍体快得多，这一现象可能与神经纤维延伸的不同动态和/或三倍体脊髓运动神经元数量和大小的改变有关。尽管二倍体和三倍体从IX期到XVIII期的正常肢体发育相同，但三倍体的再生速度几乎是二倍体的两倍。这种改变神经与外周靶标数量关系的非侵入性方法的数据表明，这是一种在发育过程中逐渐丧失再生能力的动物中研究神经依赖性肢体再生的独特方法。
