Holder N, Clarke J D, Tonge D
Anatomy & Human Biology Department, King's College London, Strand, UK.
Development. 1987 Apr;99(4):577-87. doi: 10.1242/dev.99.4.577.
Sensory fibres from dorsal root ganglia (DRG) enter the spinal cord and run within a clearly defined ipsilateral pathway, the dorsal column, which lies in the dorsal funiculus. We have examined the characteristics of this pathway as a defined substrate for dorsal column axons in Rana temporaria tadpoles by rotating the thoracic spinal cord through 180 degrees from dorsal to ventral. Using HRP as a neuronal tracer we establish that many dorsal column axons from the hindlimb locate the ipsilateral or contralateral dorsal column pathway in the rotated cord. Other axons locate and grow caudally down the contralateral dorsal column returning to the lumbar region. Axons of the dorsal column never take an inappropriate pathway except at the transection sites where they negotiate abnormal routes to reach the contralateral or ipsilateral dorsal columns in normally positioned or rotated cord. The results demonstrate that the dorsal columns act as highly specific pathways for axons from DRG neurones but the axons' interactions with the pathway do not control the craniocaudal or left-right options for growth.
来自背根神经节（DRG）的感觉纤维进入脊髓，并在一个明确界定的同侧通路——背柱中运行，背柱位于背侧索内。我们通过将牛蛙蝌蚪的胸段脊髓从背侧旋转180度至腹侧，研究了该通路作为背柱轴突特定底物的特征。使用辣根过氧化物酶（HRP）作为神经元示踪剂，我们确定来自后肢的许多背柱轴突在旋转的脊髓中定位到同侧或对侧背柱通路。其他轴突定位并沿对侧背柱向尾侧生长，回到腰段区域。背柱的轴突除了在横断部位外，从不走不合适的通路，在横断部位它们会以异常路径在正常位置或旋转的脊髓中到达对侧或同侧背柱。结果表明，背柱是DRG神经元轴突的高度特异性通路，但轴突与该通路的相互作用并不控制生长的头尾或左右选择。
