中文摘要：

目的：观察电针耐受大鼠中脑导水管周围灰质外侧区（lateral periaqueductal gray,l PAG）中P2X7受体表达变化并探讨其拮抗剂（A-740003）在电针耐受中的作用。方法：SD大鼠分为对照组、假电针组、电针耐受组、正常＋生理盐水组、正常＋A-740003组、电针耐受＋生理盐水组、电针耐受＋A-740003（1、10、100 nmol）组。电针耐受组大鼠给予连续电针刺激6天,首先检测大鼠机械痛阈变化百分数,并应用免疫组化法检测电针后第6天大鼠l PAG中P2X7受体蛋白表达情况;在电针耐受大鼠l PAG中注射不同剂量的A-740003后再次电针刺激,观察A-740003对电针耐受的影响。结果：多次电针刺激后,大鼠机械痛阈变化百分数逐渐减少伴l PAG中P2X7受体的表达增多;A-740003可翻转电针耐受的形成。结论：l PAG中P2X7受体活化促进大鼠电针耐受形成。

英文摘要：

Objective： This study aimed to investigate the expression of the P2X7 receptors in the lateral midbrain periaqueductal gray（l PAG） in electroacupuncture（EA） tolerant rats and the role of A-740003, a selective antagonist of P2X7 receptor, in EA tolerance. Methods： Sprague-Dawley（SD） rats were randomly divided into 9 groups, namely, control group, sham EA group, EA tolerance group, normal plus physiological saline（NS） group, normal plus A-740003 group, EA tolerance plus saline group and EA tolerance plus A-740003（1, 10 and 100 nmol, respectively） groups. The control group, sham EA group and EA tolerance group were administered for 6 consecutive days of the EA stimulation and tested for mechanical withdrawal thresholds（MWT） by using an electronic von Frey anesthesiometer. The immunohistochemical technique was used to detect the expression of P2X7 receptors in the l PAG on day 6 post-EA. The effects of intra-l PAG injection of NS or different doses of A-740003 on MWT were studied on EA tolerant rats. Results： In EA tolerant rats, the MWT percentage change gradually decreased with an up-regulation of the P2X7 receptor expression in the l PAG. The intra-l PAG injection of A-740003 at doses of 10 and 100 nmol increased the MWT percentage changes. Conclusion： Multiple EA treatments can induce EA tolerance via the activation of P2X7 receptors in the l PAG in rats.