Lazarov Nikolai E
Department of Anatomy, Faculty of Medicine, Thracian University, 11 Armejska Street, BG-6003 Stara Zagora, Bulgaria.
Prog Neurobiol. 2002 Jan;66(1):19-59. doi: 10.1016/s0301-0082(01)00021-1.
A characteristic peculiarity of the trigeminal sensory system is the presence of two distinct populations of primary afferent neurons. Most of their cell bodies are located in the trigeminal ganglion (TG) but part of them lie in the mesencephalic trigeminal nucleus (MTN). This review compares the neurochemical content of central versus peripheral trigeminal primary afferent neurons. In the TG, two subpopulations of primary sensory neurons, containing immunoreactive (IR) material, are identified: a number of glutamate (Glu)-, substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)-, cholecystokinin (CCK)-, somatostatin (SOM)-, vasoactive intestinal polypeptide (VIP)- and galanin (GAL)-IR ganglion cells with small and medium-sized somata, and relatively less numerous larger-sized neuropeptide Y (NPY)- and peptide 19 (PEP 19)-IR trigeminal neurons. In addition, many nitric oxide synthase (NOS)- and parvalbumin (PV)-IR cells of all sizes as well as fewer, mostly large, calbindin D-28k (CB)-containing neurons are seen. The majority of the large ganglion cells are surrounded by SP-, CGRP-, SOM-, CCK-, VIP-, NOS- and serotonin (SER)-IR perisomatic networks. In the MTN, the main subpopulation of large-sized neurons display Glu-immunoreactivity. Additionally, numerous large MTN neurons exhibit PV- and CB-immunostaining. On the other hand, certain small MTN neurons, most likely interneurons, are found to be GABAergic. Furthermore, NOS-containing neurons can be detected in the caudal and the mesencephalic-pontine junction portions of the nucleus. Conversely, no immunoreactivity to any of the examined neuropeptides is observed in the cell bodies of MTN neurons but these are encircled by peptidergic, catecholaminergic, serotonergic and nitrergic perineuronal arborizations in a basket-like manner. Such a discrepancy in the neurochemical features suggests that the differently fated embryonic migration, synaptogenesis, and peripheral and central target field innervation can possibly affect the individual neurochemical phenotypes of trigeminal primary afferent neurons.
三叉神经感觉系统的一个独特特征是存在两种不同类型的初级传入神经元。它们的大多数细胞体位于三叉神经节（TG），但部分细胞体位于三叉神经中脑核（MTN）。本综述比较了中枢与外周三叉神经初级传入神经元的神经化学内容。在TG中，可识别出两个含有免疫反应性（IR）物质的初级感觉神经元亚群：一些谷氨酸（Glu）、P物质（SP）、神经激肽A（NKA）、降钙素基因相关肽（CGRP）、胆囊收缩素（CCK）、生长抑素（SOM）、血管活性肠多肽（VIP）和甘丙肽（GAL）免疫反应性的中小型细胞体神经节细胞，以及数量相对较少的较大型神经肽Y（NPY）和肽19（PEP 19）免疫反应性三叉神经元。此外，可见各种大小的许多一氧化氮合酶（NOS）和小白蛋白（PV）免疫反应性细胞，以及较少的、大多为大型的含钙结合蛋白D - 28k（CB）的神经元。大多数大型神经节细胞被SP、CGRP、SOM、CCK、VIP、NOS和5 - 羟色胺（SER）免疫反应性的胞体周围网络所包围。在MTN中，大型神经元的主要亚群表现出Glu免疫反应性。此外，许多大型MTN神经元呈现PV和CB免疫染色。另一方面，某些小型MTN神经元，很可能是中间神经元，被发现是γ-氨基丁酸能的。此外，在该核的尾部和中脑桥脑交界处可检测到含NOS的神经元。相反，在MTN神经元的细胞体中未观察到对任何所检测神经肽的免疫反应性，但它们被肽能、儿茶酚胺能、5 - 羟色胺能和一氧化氮能的神经元周围分支以篮状方式环绕。这种神经化学特征的差异表明，不同的胚胎迁移命运、突触形成以及外周和中枢靶场神经支配可能会影响三叉神经初级传入神经元的个体神经化学表型。
