Studies on Dendroarchitecture and Dendrogenesis of Spinal Motor Meuron Pool with a New Labeling Technique

通过肌内注射结合霍乱毒素b亚基的辣根过氧化酶，研究了鸡脊髓特定后肢肌肉运动神经元的树突结构。髂胫后肌和股胫后肌的运动神经元池（MNP）分别位于腰骶段（LS） 1-4和1-3外侧运动柱的背外侧。虽然股胫MNP的树突延伸比髂胫后MNP的树突延伸少且短，但两者的树突分布模式非常相似。树突分布在白质和灰质中分布均匀。髂胫后肌MNP有向各方向延伸的树突。大量的树突穿透到白质中，其中许多到达外侧和腹侧的耻骨头表面，树突指向背角的底部。髂腓骨（LS4-7）和尾屈肌（LS6-8）的MNPs均有树突状树，沿外侧运动柱的外侧和腹侧边界延伸。从这些观察中我们得出结论，支配鸡不同后肢肌肉的MNPs树突分布有很大差异。

Dendroarchitecture of motoneurons innervating specific hindlimb muscles was studied in the chick spinal cord by the use of intramuscular injections of horseradish peroxidase conjugated with cholera toxin subunit B. Motoneuron pools (MNP) of the posterior iliotibial and femorotibial muscles were located at the dorsolateral part of the lateral motor column of the lumbosacral spinal segments (LS) 1-4 and 1-3, respectively. Although dendritic extensions of femorotibial MNP was fewer and shorter than that of the posterior iliotibial MNP, distribution pattern of dendrites of these two MNPs were quite similar. Dendritic profiles were equally distributed in the white and gray matters. The MNP of posterior iliotibial muscle have dendrites extending all the directions. A large number of dendrites penetrated in the white matter, and many of them reached to the pial surface of the lateral and ventral funiculi, Dendrites directing to the dorsomedialwards reached to the base of the dorsal horn. MNPs of both the iliofibular (LS4-7) and caudilioflexorius (LS6-8) had dendritic trees, which extended along both lateral and ventral border of the lateral motor column. From these observation we concluded that there are major differences in the distribution of dendrites of MNPs innervating different hind limb muscles of the chicken.