Analysis of development, differentiation, and remodeling of the pelvic visceral motor nervous system

为了研究包括骨盆内脏运动神经元在内的腰骶运动神经元群的发育和分化，我们检测了LIM蛋白、胰岛-1和胰岛-2的表达，这些蛋白被认为在诱导运动神经元的命运中起作用。Islet-1在体细胞运动神经元组和由副交感神经节前神经元组成的中外侧核中以E13.5的水平表达，但在运动神经元组中，除了与Onuf核相同的背外侧核尾侧水平外，其余各组均显著下调。因此，Onuf的细胞核在发育过程中具有不同于其他体细胞运动神经元群的化学特性。此外，在体细胞运动神经元组中，不同时空的胰岛-1表达模式使我们假设胰岛-1可能不仅与运动神经元的命运诱导有关，而且与运动神经元组的分化有关。另一方面，我们还以TRPV1和CGRP为标记物，检测了初级感觉神经元对脊髓的投射，以探讨盆腔内脏神经反射通路的发展，并阐明了E16建立了初级感觉神经元直接投射到副交感神经节前神经元的反射通路。在系统发育方面，对爪蟾交感神经节前神经元的一般组织进行了全面的研究。交感神经节前神经元中外侧分成四列，大部分神经元位于内侧的插状核和外侧的中外侧核。此外，与哺乳动物不同的是，通过内脏神经调控包括盆腔器官在内的腹部脏器的神经元聚集在中间外侧柱中。

In order to investigate the development and differentiation of the lumbosacral motoneuronal groups including the pelvic visceral motoneurons, we examined the expression of LIM proteins, Islet-1 and Islet-2, which are assumed to play a role in inducing motoneuronal fate. Islet-1 was expressed at E13.5 in the somatic motoneuronal groups and in the intermediolateral nucleus consisting of the parasympathetic preganglionic neurons, but was downregulated remarkably in the motoneuronal groups, except for the caudal level of the dorsolateral nucleus, which are homologous to the nucleus of Onuf. Therefore, Onuf's nucleus has a chemical identity different from any other somatic motoneuronal groups in the developmental process. Furthermore, differential spatiotemporal Islet-1 expression pattern among somatic motoneuronal groups led us to suppose that Islet-1 might be concerned with not only inducing motoneuronal fate as already shown, but also with the differentiation of motoneuronal groups. On the other hand, we also examine the primary sensory projections to the spinal cord using TRPV1 and CGRP as markers in order to investigate the development of the reflex pathway regarding pelvic visceral nerves, and elucidated that the reflexive pathways via direct projections of the primary sensory neurons to the parasympathetic preganglionic neurons were established by E16.In the phylogenic aspect, the general organization of the sympathetic preganglionic neurons in Xenopus was thoroughly examined. The sympathetic preganglionic neurons were divided mediolaterally into four distinct columns, and most of the neurons were located in the medially located intercalated nucleus, and in the laterally located intermediolateral nucleus. Furthermore, neurons concerned with the regulation of the abdominal viscera including the pelvic organs via the splanchnic nerves were clustered in the intermediolateral columns, unlike in mammals.