大鼠初级感觉神经元P2X3受体的表达及其与SP的关系

EXPRESSION OF ADENOSINE TRIPHOSPHATE P2X3 RECEPTOR AND ITS RELATION WITH SUBSTANCE P IN RAT PRIMARY SENSORY NEURONS

目的研究在大鼠初级感觉神经元细胞上P2X3受体的表达情况及其与P物质的关系。方法取SD大鼠背根神经节(DRG)和三叉神经节(TG)固定后切片;用抗P2X3受体抗体和抗SP抗体进行免疫组织化学反应,并通过两种不同的显色方法同时进行P2X3受体和SP的双标。结果P2X3免疫反应阳性细胞主要集中在小细胞和中等细胞(其中在TG,P2X3-ir阳性神经元约占整个细胞的24.8%;在DRG约31.7%的神经元是P2X3-ir阳性),并且在DRG和TG细胞上均存在有P2X3受体和SP共存(TG上的双标细胞占P2X3-ir阳性细胞总数的36.26%,DRG上占46.81%)。结论由于ATP门控阳离子通道受体P2X3本身就与伤害性感受的初级传入有关,而它与SP的共存可提示当组织中的ATP释放时可以通过P2X3受体作用于含SP的伤害性感觉神经末梢上,促使SP释放引起痛觉过敏。

Objective To investigate the expression of P2X3 receptor subunits in rat sensory neurons and its relation to substance P （SP）. Methods SD-rat trigeminal ganglion （TG） and dorsal root ganglion （DRG） were fixed and sectioned. Anti-P2X3 and anti-SP antibodies were used to label P2X3 and SP ; then two different stains were used to achieve double immunostaining. Results P2X3-ir positive neurons were localized in small and medium cells （In TG the percentages of small, medium and large cells were 93.5%, 6. 5% and 0; in DRG these three percentages were 96. 9%, 3. 1% and 0 respectively. Colocalization of P2X3 and SP was found in TG and DRG （TG： 36. 26%, DRG： 46. 81%）. Conclusion The P2X3 receptor is an ATP-gated cation channel that is related to primary nociceptive sensory transimission. Its colocalization with SP suggests that ATP in tissues may act on nociceptive sensory nerve fibers containing SP by acting on P2X3 receptors located in the periphery, which can enhance SP release and induce hyperalgesia.