Schrøder H D
J Comp Neurol. 1980 Aug 1;192(3):567-87. doi: 10.1002/cne.901920313.
The cytoarchitecture of the motoneuron pool of the male rat was studied at the lumbo-sacral transition area, particularly in L6. In the latter segment a dorso-medial (DM), ventral (V), dorso-lateral (DL), and retrodorso-lateral group (RDL) could be defined. The DL group was associated with a prominent longitudinal dendrite bundle and the CM group with smaller transverse bundles. Moreover, close soma-somatic apposition was found between neurons in these columns. Because L6 gives rise to n. pudendus and contributes to n. ischiadicus, horseradish peroxidase (HRP) was applied to the cut n. ischiadicus and in other experiments injected into the pelvic muscles. Neurons in RDL were labeled following exposure of n. ischiadicus to HRP. Injections in m. levator ani resulted in labeled neurons in the V group, mainly below L6. Injections in m. sphincter urethrae resulted in labeled neurons in the DL group as well as neurons immediately cranial to this column. Musculus ischiocavernosus injections resulted in transport of HRP to neurons in the DL group, primarily in its medial part, and to more cranially located neurons. In addition, some neurons in the V group in L6 were labeled. Following injections in m. bulbocavernosus and m. sphincter ani, labeled neurons were found primarily in the DM group, and to a lesser extent in the V group. Histochemical investigations with staining methods for the localization of acetyl cholinesterase (AChE) and heavy metals (the Timm method) demonstrated that part of the neuropil of DL and of DM were different from the rest of the motoneuron neuropil. In the DL group the area with the diverging staining patterns corresponded to the region of the dendrite bundle. The experimental data indicated and the ultrastructural studies demonstrated that the histochemical differences could be correlated with differences in the composition of the populations of boutons. The comparison of the cytoarchitectural and histochemical data with the results obtained by the aid of the retrograde HRP tracing technique established that mm. sphincter urethrae, ischiocavernosus, bulbocavernosus, and sphincter ani were each innervated by two populations of neurons that were situated in separate areas which had different histochemical properties, and which thus probably have different compositions of their afferent inputs. The duality in the motoneuron pool that innervates the pelvic mucscle might be a reflection of the dual influence on these muscles. As all other striated muscles the pelvic muscles are under voluntary control. However, they are also tightly linked to the function of the pelvic viscera and thus under influence of the autonomic nervous system.
对雄性大鼠腰骶移行区，特别是L6节段的运动神经元池的细胞构筑进行了研究。在该节段可区分出背内侧（DM）、腹侧（V）、背外侧（DL）和后外侧组（RDL）。DL组与一束明显的纵向树突束相关，CM组与较小的横向树突束相关。此外，在这些柱内的神经元之间发现了紧密的体细胞-体细胞并置。由于L6发出阴部神经并参与坐骨神经的组成，将辣根过氧化物酶（HRP）应用于切断的坐骨神经，并在其他实验中注入盆腔肌肉。坐骨神经暴露于HRP后，RDL中的神经元被标记。注射到提肛肌中导致V组中的神经元被标记，主要在L6以下。注射到尿道括约肌中导致DL组中的神经元以及紧邻该柱颅侧的神经元被标记。阴茎海绵体肌注射导致HRP运输到DL组中的神经元，主要在其内侧部分，以及更靠颅侧的神经元。此外，L6中V组的一些神经元也被标记。在球海绵体肌和肛门括约肌注射后，主要在DM组中发现了被标记的神经元，在V组中发现的较少。用乙酰胆碱酯酶（AChE）定位染色方法和重金属（Timm法）进行的组织化学研究表明，DL和DM的部分神经纤维网与运动神经元神经纤维网的其余部分不同。在DL组中，染色模式发散的区域对应于树突束的区域。实验数据表明，超微结构研究证明，组织化学差异可能与终扣群体组成的差异相关。将细胞构筑和组织化学数据与逆行HRP追踪技术获得的结果进行比较，确定尿道括约肌、阴茎海绵体肌、球海绵体肌和肛门括约肌各自由位于不同区域的两群神经元支配，这些区域具有不同的组织化学特性，因此其传入输入组成可能也不同。支配盆腔肌肉的运动神经元池的二元性可能反映了对这些肌肉的双重影响。与所有其他横纹肌一样，盆腔肌肉受自主控制。然而，它们也与盆腔内脏的功能紧密相连，因此受自主神经系统的影响。
