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[目的]通过观察内脏高敏感模型大鼠结肠特异背根神经节(DRG)神经元P_2X_3受体表达和电生理特征,探讨P_2X_3受体在大鼠内脏高敏感性中的作用。[方法]10只幼鼠分为2组,经结直肠分别灌注乙酸诱导内脏高敏感模型(内脏高敏感组)、0.9%氯化钠溶液作对照(对照组);在结肠壁上注射1,1’-二(十八烷基)-3,3,3’,3’-四甲基吲哚羰基花青高氯酸盐(DiI)逆行神经标记的DRG神经元为结肠特异DRG神经元,用免疫荧光技术观察其P_2X_3受体表达变化和膜片钳技术进行电生理记录。[结果]内脏高敏感组与对照组大鼠比较,结肠特异DRG神经元上P_2X_3受体免疫阳性率明显增加(45.47%∶32.15%,P<0.01)、结肠特异DRG神经元静息电位和阈电流降低(P<0.05)、动作电位频率增高(P<0.05)。AWR评分值与结肠特异DRG神经元上P_2X_3受体阳性率(r=0.86,P<0.01)、2倍阈电流刺激下动作电位频率(r=0.82,P<0.01)呈正相关,与阈电流值(r=-0.77,P<0.01)呈负相关。[结论]P_2X_3受体在结肠特异DRG神经元上表达上调且DRG神经元兴奋性增加与内脏高敏感的形成有密切关系。
[Objective] To investigate the effect of P_2X_3 receptor on visceral hypersensitivity in rat visceral hypersensitivity rat model by observing the expression of P_2X_3 receptor and its electrophysiological characteristics in rat colon specific dorsal root ganglion (DRG) neurons. [Method] Ten young rats were divided into two groups. The model of visceral hypersensitivity (visceral hypersensitivity) and the control of 0.9% sodium chloride (control group) DRG neurons retrogradely labeled with 1’-dioctadecyl-3,3,3 ’, 3’-tetramethylindocarbonylcyanine perchlorate (DiI) are colon-specific DRG neurons, Immunofluorescence was used to observe the changes of P_2X_3 receptor expression and patch clamp technique for electrophysiological recording. [Results] The positive rate of P_2X_3 receptor in colon-specific DRG neurons increased significantly (45.47% vs 32. 15%, P <0.01) in the visceral hypersensitivity group compared with the control rats. The resting potentials and thresholds of the colon-specific DRG neurons The current decreased (P <0.05) and the action potential frequency increased (P <0.05). The AWR score was positively correlated with the P_2X_3 receptor positive rate (r = 0.86, P <0.01) and 2 times threshold current stimulation (r = 0.82, P <0.01) in colonic DRG neurons, (r = -0.77, P <0.01). [Conclusion] The expression of P_2X_3 receptor is up-regulated in colon-specific DRG neurons and the increased excitability of DRG neurons is closely related to the formation of visceral hypersensitivity.