Fitzgerald M
Department of Anatomy, University College, London, United Kingdom.
J Comp Neurol. 1985 Oct 22;240(4):407-13. doi: 10.1002/cne.902400408.
Transganglionic labelling of the saphenous nerve in rats with WGA-HRP revealed the central distribution of its terminals in the lumbar dorsal horn. The terminal field was clearly defined and consistent in rats aged between day 6 and day 90. If, however, the sciatic nerve was sectioned on day 1 of postnatal life, the saphenous terminal field expanded to occupy twice the normal area (measured between the L2 and L4 boundaries). The spread was caudal, medial, and lateral into areas normally occupied by sciatic nerve terminals. This sprouting was very weak if the sciatic nerve was sectioned later in postnatal life, on day 5, and nonexistent if sectioning took place on day 10. Crushing the sciatic nerve on day 1 also triggered the effect but the spread of the terminal field was less than that produced by section of the sciatic nerve. There was no evidence of sprouting from the contralateral intact sciatic nerve. The results demonstrate the necessity of intact afferent input during a critical period of neonatal life in order to maintain the precise somatotopic termination pattern of dorsal root afferents.
用WGA-HRP对大鼠隐神经进行跨神经节标记，揭示了其终末在腰段背角的中枢分布。在出生后第6天至第90天的大鼠中，终末场清晰界定且一致。然而，如果在出生后第1天将坐骨神经切断，隐神经终末场会扩大，占据正常面积的两倍（在L2和L4边界之间测量）。扩展是向尾侧、内侧和外侧进入通常由坐骨神经终末占据的区域。如果在出生后第5天切断坐骨神经，这种发芽非常微弱；如果在第10天切断，则不存在发芽现象。在第1天挤压坐骨神经也会引发这种效应，但终末场的扩展小于切断坐骨神经所产生的扩展。没有证据表明对侧完整的坐骨神经会发芽。结果表明，在新生儿生命的关键时期，完整的传入输入对于维持背根传入纤维精确的躯体定位终止模式是必要的。
