Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai, 980-8575, Japan.
Division of Oral Diagnosis, Graduate School of Dentistry, Tohoku University, Sendai, 980-8575, Japan.
Tissue Cell. 2020 Jun;64:101344. doi: 10.1016/j.tice.2020.101344. Epub 2020 Feb 9.
The jugular ganglion (JG) contains sensory neurons of the vagus nerve which innervate somatic and visceral structures in cranial and cervical regions. In this study, the number of sensory neurons in the human JG was investigated. And, the morphology of sensory neurons in the human JG and nodose ganglion (NG) was compared. The estimated number of JG neurons was 2721.8-9301.1 (average number of sensory neurons ± S.D. = 7975.1 ± 3312.8). There was no significant difference in sizes of the neuronal cell body and nucleus within the JG (cell body, 1128.8 ± 99.7 μ m; nucleus, 127.7 ± 20.8 μ m) and NG (cell body, 963.8 ± 225.7 μ m; nucleus, 123.2 ± 32.3 μ m). These findings indicate that most of sensory neurons show the similar morphology in the JG and NG. Our immunohistochemical method also demonstrated the distribution of ion channels, neurotransmitter agents and calcium-binding proteins in the human JG. Numerous JG neurons were immunoreactive for transient receptor potential cation channel subfamily V member 1 (TRPV1, mean ± SD = 19.9 ± 11.5 %) and calcitonin gene-related peptide (CGRP, 28.4 ± 6.7 %). A moderate number of JG neurons contained TRPV2 (12.0 ± 4.7 %), substance P (SP, 15.7 ± 6.9 %) and secreted protein, acidic and rich in cysteine-like 1 (SPARCL1, 14.6 ± 7.4 %). A few JG neurons had vesicular glutamate transporter 2 (VGLUT2, 5.6 ± 2.9 %) and parvalbumin (PV, 2.3 ± 1.4 %). SP- and TRPV2-containing JG neurons had mainly small and medium-sized cell bodies, respectively. TRPV1- and VGLUT2- containing JG neurons were small to medium-sized. CGRP- and SPARCL1-containing JG neurons were of various cell body sizes. Sensory neurons in the human JG were mostly free of vasoactive intestinal polypeptide (VIP), tyrosine hydroxylase (TH) and neuropeptide Y (NPY). In the external auditory canal skin, subepithelial nerve fibers contained TRPV1, TRPV2, SP, CGRP and VGLUT2. Perivascular nerve fibers also had TRPV1, TRPV2, SP, CGRP, VIP, NPY and TH. However, PV- and SPARCL1-containing nerve endings could not be seen in the external auditory canal. It is likely that sensory neurons in the human JG can transduce nociceptive and mechanoreceptive information from the external auditory canal. Theses neurons may be also associated with neurogenic inflammation in the external auditory canal and ear-cough reflex through the vagus nerve.
颈静脉节（JG）包含支配颅颈部躯体和内脏结构的迷走神经感觉神经元。本研究旨在调查人类 JG 中的感觉神经元数量，并比较 JG 和结状神经节（NG）中感觉神经元的形态。估计 JG 神经元数量为 2721.8-9301.1（感觉神经元的平均数量±S.D.=7975.1±3312.8）。JG 和 NG 内神经元胞体和核大小无显著差异（胞体 1128.8±99.7μm；核 127.7±20.8μm）。我们的免疫组织化学方法还证明了人类 JG 中离子通道、神经递质和钙结合蛋白的分布。大量 JG 神经元对瞬时受体电位阳离子通道亚家族 V 成员 1（TRPV1，平均值±SD=19.9±11.5%）和降钙素基因相关肽（CGRP，28.4±6.7%）呈免疫反应性。相当数量的 JG 神经元含有 TRPV2（12.0±4.7%）、P 物质（SP，15.7±6.9%）和分泌蛋白、富含半胱氨酸的酸性蛋白 1（SPARCL1，14.6±7.4%）。少数 JG 神经元含有囊泡谷氨酸转运体 2（VGLUT2，5.6±2.9%）和钙结合蛋白（PV，2.3±1.4%）。含有 SP 和 TRPV2 的 JG 神经元主要具有中小细胞体，而含有 TRPV1 和 VGLUT2 的 JG 神经元则为中小细胞体。含有 CGRP 和 SPARCL1 的 JG 神经元具有各种大小的细胞体。人类 JG 中的感觉神经元主要不含有血管活性肠肽（VIP）、酪氨酸羟化酶（TH）和神经肽 Y（NPY）。在外耳道皮肤中，上皮下神经纤维含有 TRPV1、TRPV2、SP、CGRP 和 VGLUT2。血管周围神经纤维也含有 TRPV1、TRPV2、SP、CGRP、VIP、NPY 和 TH。然而，在外耳道中未观察到含有 PV 和 SPARCL1 的神经末梢。因此，人类 JG 中的感觉神经元可能在外耳道中传递伤害性和机械性感觉信息。这些神经元可能通过迷走神经与外耳道中的神经源性炎症和耳咳反射有关。
