背根神经节P2X3受体在大鼠切口痛形成中的作用

目的 评价背根神经节P2X3受体在大鼠切口痛形成中的作用.方法 健康雄性SD大鼠24只,体重200～220 g,随机分为3组(n=8):对照组(C组)、切口痛组(IP组)和P2X3受体拮抗剂组(A组).IP组和A组制备大鼠左后趾部切口痛模型.模型建立后30 min,A组左后爪底皮下注射P2X3受体特异性拮抗剂TNP-ATP 200 nmol,C组和IP组注射等容量生理盐水.采用累积疼痛评分法,评定注药后1 h内大鼠疼痛行为学变化.注药后2 h时处死大鼠,取背根神经节,测定P2 X3受体表达和细胞内Ca2+浓度.结果 与C组比较,IP组和A组累积疼痛评分和Ca2+浓度升高,P2X3受体表达上调(P＜0.05);与IP组比较,A组累积疼痛评分和Ca2+浓度降低,P2X3受体表达下调(P＜0.05).结论 背根神经节P2X3受体参与了大鼠切口痛的形成,其机制可能与升高细胞内Ca2+浓度有关.

Role of P2X3 receptors in dorsal root ganglion in development of incisional pain in rats

Objective To evaluate the role of P2X3 receptors in dorsal root ganglion in development of incisional pain in rats.Methods Twenty-four healthy male SD rats weighing 200-220 g were randomly divided into 3 groups(n = 8 each): control group(group C),incisional pain(group IP)and P2X3 receptor antagonist + IP group(group A).In group IP and A,a 1 cm longitudinal incision was made in the plantar surface of left hindpaw according to the method described by Brennan et al.in isoflurane-anesthetized rats.P2X3 receptor antagonist TNP-ATP 200 nmol was injected into the plantar surface of left hindpaw 30 min after plantar incision was made in group A,while equal volume of normal saline was given instead of TNP-ATP in group C and IP.The behavior of the hindpaw of the rats were assessed using cumulative pain score within 1 h after injection.The animals were sacri ficed 2 h after injection and the dorsal root ganglion was removed for determination of P2X3 receptor expression and intracellular Ca2+ concentrations.Results The cumulative pain scores,P2X3 receptor expression and Ca2 + concentrations were significantly higher in group IP and A than in group C(P ＜ 0.05).The cumulative pain scores,P2X3 receptor expression and Ca2+ concentrations were significantly lower in group A than in group IP(P ＜0.05).Conclusion P2X3 receptors in dorsal root ganglion is involved in the development of incisional pain through increasing intracellular Ca2+ concentrations in rats.