Takahashi Sato Kaoru, Satoh Koichiro, Sekiguchi Miho, Kikuchi Shin-ichi, Konno Shin-ichi, Murakawa Masahiro, Rydevik Björn, Olmarker Kjell
Department of Anesthesiology, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima City, Fukushima, Japan.
Fukushima J Med Sci. 2012;58(1):17-21. doi: 10.5387/fms.58.17.
The P2X(3) receptor is a ligand-gated cation channel that is activated by extra cellular adenosine triphosphate (ATP) found in the dorsal root, trigeminal and nodose ganglia. It is one of the receptors transmitting nociceptive information of injuries and inflammation of the periphery by endogenous ATP released from damaged cells. The present study was performed in order to evaluate if there was an increased expression of P2X(3)-immunoreactivity in dorsal root ganglion (DRG) neurons after experimental disc herniation. There were four groups: exposure of the left L4 dorsal root ganglion and incision of the L4-L5 disc, exposure and slight displacement of the left L4 dorsal ganglion, sham exposure of the L4 dorsal root ganglion, and normal. Seven days after surgery, the DRG's were collected, sectioned and stained immunohistochemically for the P2X(3) receptor. The expression of P2X(3) increased significantly following incision of the L4-5 disc compared to the normal group. Sham surgery induced a minor, although statistically significant increase. Mechanical displacement did not induce any increased expression of the receptors. The study demonstrates that expression of the P2X(3)receptors in the DRG may be induced by local application of nucleus pulposus. This may increase our understanding of the pathophysiologic mechanisms related to disc herniation and sciatica.
P2X(3)受体是一种配体门控阳离子通道，可被背根神经节、三叉神经节和结节神经节中的细胞外三磷酸腺苷（ATP）激活。它是通过受损细胞释放的内源性ATP传递外周损伤和炎症伤害性信息的受体之一。本研究旨在评估实验性椎间盘突出后背根神经节（DRG）神经元中P2X(3)免疫反应性表达是否增加。实验分为四组：暴露左侧L4背根神经节并切开L4-L5椎间盘、暴露并轻微移位左侧L4背根神经节、假暴露L4背根神经节以及正常组。术后7天，收集DRG，切片并进行P2X(3)受体免疫组化染色。与正常组相比，切开L4-5椎间盘后P2X(3)的表达显著增加。假手术虽有轻微增加，但具有统计学意义。机械移位未诱导受体表达增加。该研究表明，DRG中P2X(3)受体的表达可能由局部应用髓核诱导。这可能会增加我们对与椎间盘突出和坐骨神经痛相关的病理生理机制的理解。
