Kim Yun Sook, Kim Sung Kuk, Lee Jae Sik, Ko Sang Jin, Bae Yong Chul
Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea.
Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea.
Brain Res. 2018 Jul 1;1690:31-39. doi: 10.1016/j.brainres.2018.04.010. Epub 2018 Apr 9.
Transient receptor potential ankyrin 1 (TRPA1), a cold receptor in sensory neurons activated by a variety of stimuli, is implicated in nociception and mechanotransduction. To help understand the vesicular glutamate transporter (VGLUT)-mediated glutamate signaling in TRPA1-immunopositive (+) neurons, we examined the expression of VGLUT1 and VGLUT2 in the TRPA1+ neurons in the male rat trigeminal ganglion (n = 19) under normal conditions and following experimental inflammation in the vibrissal pad by light microscopic immunohistochemistry (n = 11), western blot (n = 8), and quantitative analysis. One half (50.8%, 250/492) of the TRPA1+ neurons expressed VGLUT2, and a small fraction (8.3%, 57/683) also expressed VGLUT1. The majority of the VGLUT2-expressing TRPA1+ (VGLUT2+/TRPA1+) neurons coexpressed the markers of peptidergic and non-peptidergic neurons, CGRP, IB4, and TRPV1 but not the markers of neurons with myelinated fibers, NF200 and parvalbumin. In contrast, most VGLUT1+/TRPA1+ neurons coexpressed NF200 and parvalbumin but rarely expressed CGRP, IB4, or TRPV1. Following experimental inflammation, the fraction of VGLUT2+ (experimental vs. control: 34.7% vs. 22.3%), TRPA1+ (39.3% vs. 25.3%), and VGLUT2+/TRPA1+ (60.7% vs. 49.7%) neurons and the protein levels for TRPA1 and VGLUT2 increased significantly, compared to control, whereas the fraction of VGLUT1+ and VGLUT1+/TRPA1+ neurons and the protein level for VGLUT1 remained unchanged. These findings suggest that both VGLUT1 and VGLUT2 are involved in the glutamate signaling in TRPA1+ neurons under normal conditions in the male rats, and raise a possibility that VGLUT2 may play a role in the TRPA1-induced hypersensitivity following inflammation.
瞬时受体电位锚蛋白1（TRPA1）是一种感觉神经元中的冷受体，可被多种刺激激活，与伤害感受和机械转导有关。为了帮助理解囊泡谷氨酸转运体（VGLUT）介导的TRPA1免疫阳性（+）神经元中的谷氨酸信号传导，我们通过光学显微镜免疫组织化学（n = 11）、蛋白质印迹法（n = 8）和定量分析，研究了正常条件下以及触须垫实验性炎症后雄性大鼠三叉神经节（n = 19）中TRPA1 +神经元中VGLUT1和VGLUT2的表达。一半（50.8%，250/492）的TRPA1 +神经元表达VGLUT2，一小部分（8.3%，57/683）也表达VGLUT1。大多数表达VGLUT2的TRPA1 +（VGLUT2 + /TRPA1 +）神经元共表达肽能和非肽能神经元的标志物CGRP、IB4和TRPV1，但不表达有髓纤维神经元的标志物NF200和小白蛋白。相反，大多数VGLUT1 + /TRPA1 +神经元共表达NF200和小白蛋白，但很少表达CGRP、IB4或TRPV1。实验性炎症后，与对照组相比，VGLUT2 +（实验组与对照组：34.7%对22.3%）、TRPA1 +（39.3%对25.3%）和VGLUT2 + /TRPA1 +（60.7%对49.7%）神经元的比例以及TRPA1和VGLUT2的蛋白质水平显著增加，而VGLUT1 +和VGLUT1 + /TRPA1 +神经元的比例以及VGLUT1的蛋白质水平保持不变。这些发现表明，在雄性大鼠的正常条件下，VGLUT1和VGLUT2都参与TRPA1 +神经元中的谷氨酸信号传导，并增加了VGLUT2可能在炎症后TRPA1诱导的超敏反应中起作用的可能性。
