Morphological and functional studies on NO producing neurons in the brainstem involved in pral sensori-motor functions

NADPH黄递酶（NADPH-d）组织化学染色显示大鼠下脑干有一个明显的神经元群。NADPH-d染色显示三叉神经口侧脊束核（Vo）和孤束核（Sn）内存在Golgi样网络。三叉旁核（paratrigeminal nucleus，paraV）、三叉神经脊束极间核（spinal trigerninal nucleus interpolaris，Vi）与尾侧核（spinal trigerninal nucleus，Vc）之间的间隙区（gap region）、Vc的浅带（superior zone）也有神经元染色，Vc的大细胞带染色较少。Vo和Sn内NADPH-d阳性神经元的分布与口内结构神经的WGA-HRP跨神经节标记的中央终末区重叠。Vi和Vc内NADPH-d阳性神经元的分布与支配口内和口外结构的神经的中央终末区重叠。切断支配口内结构的神经后1 ~ 2周，Vo/Sn区标记神经元数量减少。这些结果表明，NADPH-d阳性神经元在下脑干可以跨突触的口内结构的初级传入调节。在胚胎第12天（EI 2），脑中没有神经元被NADPH-d染色，而血管被染色。E15时，Vo和Sn出现标记神经元。生后第4天（P4），Vc大细胞区出现标记。P10时，V旁和Vc浅带出现标记。在各核团首次表达NADPH-d后，标记增强或维持至成年期。非常早期出现的NADPH-d标记在Vo和Sn，这之前出现的NADPH-d在脑干的其他地方，表明一氧化氮/环磷酸鸟苷系统有一个重要的作用，原始orofacial感觉运动反射功能。

NADPH-diaphorase (NADPH-d) histochemical staining demonstrated a distinct neural group in the lower brainstem of rats. The NADPH-d stain revealed a Golgi-like network in the dorsomedial spinal trigeminal nucleus oralis (Vo) and rostrolateral solitary tract nucleus (Sn). Another neural group was stained in the paratrigeminal nucleus (paraV), gap region between spinal trigerninal nuclei interpolaris (Vi) and caudalis (Vc), superficial zone of Vc, and much less in the magnocellular zone of Vc. The distribution of NADPH-d-positive neurons in Vo and Sn overlapped mostly with the central terminal area labeled transganglionically with WGA-HRP from nerves innervating the intraoral structures. The distribution of NADPH-d-posibve neurons in Vi and Vc overlapped with the central terminal area from nerves innervating intra- and extra-oral structures. The number of labeled neurons in Vo/Sn decreased one to two weeks after transection of nerves innervating intraoral structures. These results show that NADPH-d-positive neurons in the lower brainstem could be regulated trans-synaptically by primary afferents from the intraoral structures. On embryonic day 12 (EI2), no neurons in the brain were stained for NADPH-d, while blood vessels were stained. On E15, labeled neurons appeared in Vo and Sn. On postnatal day 4 (P4), labeling appeared in the magnocellular zone of Vc. On P10, labeling appeared in paraV and the superficial zone of Vc. After the first expression of NADPH-d in each nuclei, the labeling increased or maintained to the adulthood. The very early appearance of NADPH-d labeling in Vo and Sn, which precedes the appearance of NADPH-d elsewhere in the brainstem, suggests that the nitric oxide/cyclic guanosine monophosphate system has an important role for primitive orofacial sensorimotor reflexive functions.