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

为了研究包括盆腔内脏运动神经元在内的腰骶部运动神经元群的发育和分化，我们检测了LIM蛋白，Islet-1和Islet-2的表达，这两个蛋白被认为在诱导运动神经元命运中起作用。胰岛-1在体细胞运动神经元组和由副交感节前神经元组成的中间外侧核E13.5处有表达，但在运动神经元组表达显著下调，与Onuf核同源的背外侧核尾侧水平除外。因此，在发育过程中，Onuf核具有不同于任何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群间表达的时空差异模式使我们推测，Islet-1可能不仅与诱导运动神经元命运有关，而且还与运动神经元群间的分化有关。另一方面，我们还用TRPV1和CGRP作为标记物研究了初级感觉投射到脊髓的情况，以探讨盆腔内脏神经反射通路的发展，并阐明初级感觉神经元直接投射到副交感节前神经元的反射通路是在E16建立的。在系统发育方面，我们对非洲爪哇交感节前神经元的一般组织进行了全面的研究。交感节前神经元在内侧分为4个不同的柱状结构，大部分位于内侧的中间核和外侧的中间外侧核。此外，与哺乳动物不同，通过内脏神经调节包括盆腔器官在内的腹部内脏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.