Dohrn C S, Mullett M A, Price R H, Beitz A J
Department of Veterinary PathoBiology, College of Veterinary Medicine, University of Minnesota, St. Paul 55408.
J Comp Neurol. 1994 Aug 15;346(3):449-60. doi: 10.1002/cne.903460308.
The spinal trigeminal nucleus is involved in the transmission of orofacial sensory information. Neither the distribution of the neuromessenger, nitric oxide, within the trigeminal system nor the possible relationship of this simple gas with trigeminothalamic neurons has been carefully studied. Using immunocytochemical (against nitric oxide synthase) and histochemical (NADPH-diaphorase staining) techniques, we have found that nitric oxide neurons and processes are more prominent in the nucleus caudalis and the dorsomedial aspect of the nucleus oralis than in other spinal trigeminal regions. To study the relationship of nitric oxide to trigeminothalamic neurons and intertrigeminal interneurons of the spinal trigeminal nucleus, spinal trigeminal neurons were retrogradely labeled with fluorogold by thalamic injections or by injections into the junction of the nucleus interpolaris and nucleus caudalis. Medullary sections were subsequently processed with NADPH-diaphorase histochemistry. None of the diaphorase-stained neurons in the spinal trigeminal nucleus was found to contain fluorogold; however, some diaphorase-stained processes were found in close proximity to trigeminothalamic neurons. Following spinal trigeminal nucleus injections, many diaphorase-stained neurons were found to contain fluorogold, especially in the nucleus caudalis, suggesting that nitric oxide-containing neurons in the spinal trigeminal nucleus are intertrigeminal interneurons. Collectively, these data indicate that nitric oxide is most prominent in interneurons located in nucleus caudalis and that these interneurons give rise to processes that appose trigeminothalamic neurons, raising the possibility that they may indirectly influence orofacial nociceptive processing at the level of the spinal trigeminal nucleus via nitric oxide production.
三叉神经脊束核参与口面部感觉信息的传递。神经信使一氧化氮在三叉神经系统内的分布，以及这种简单气体与三叉丘脑神经元之间可能存在的关系，均未得到仔细研究。我们运用免疫细胞化学技术（针对一氧化氮合酶）和组织化学技术（NADPH-黄递酶染色）发现，一氧化氮神经元及其突起在尾侧核和口侧核的背内侧比在三叉神经脊束核的其他区域更为显著。为了研究一氧化氮与三叉神经脊束核的三叉丘脑神经元及三叉神经间神经元之间的关系，通过向丘脑注射或向极间核与尾侧核交界处注射荧光金，对三叉神经脊束核神经元进行逆行标记。随后，对延髓切片进行NADPH-黄递酶组织化学处理。在三叉神经脊束核中，未发现黄递酶染色的神经元含有荧光金；然而，在靠近三叉丘脑神经元的位置发现了一些黄递酶染色的突起。在向三叉神经脊束核注射后，发现许多黄递酶染色的神经元含有荧光金，尤其是在尾侧核，这表明三叉神经脊束核中含一氧化氮的神经元是三叉神经间神经元。总体而言，这些数据表明一氧化氮在位于尾侧核的中间神经元中最为显著，并且这些中间神经元产生的突起与三叉丘脑神经元相邻，这增加了它们可能通过产生一氧化氮在三叉神经脊束核水平间接影响口面部伤害性感受处理的可能性。
