摘要目的 评价急性吗啡耐受或炎性痛大鼠脊髓背角和背根神经节嘌呤受体P2Y4 (P2X4R)表达的变化.方法 雄性SD大鼠30只,采用随机数字表法,将大鼠随机分为3组:生理盐水组(NS组,n=5)、急性吗啡耐受组(M组,n=5)和炎性痛组(F组,n=20).F组建立福尔马林炎性痛模型,M组和NS组鞘内注射吗啡或生理盐水,10 μg(10 μl)/次,2 h/次,连续6次,最后1次给药后2h处死取脊髓背角和背根神经节.NS组和M组分别于每次给药后(T1-6)测定热刺激缩足反射潜伏期(PWL),F组于致炎后4、7、10和14d时随机取5只大鼠测定PWL后处死取脊髓背角和背根神经节,采用免疫组化法检测P2X4R表达.结果 与基础值比较,F组致炎后4～14 d PWL明显降低,M组T1-5时PWL升高,T6时PWL差异无统计学意义(P＞0.05).与NS组比较,M组脊髓背角和背根神经节P2X4R表达上调,F组在致炎后第4天脊髓背角和背根神经节P2X4R表达上调,于第7天时P2X4R表达至峰值,第10天和第14天时P2X4R表达逐渐下调(P＜0.01).结论 急性吗啡耐受或炎性痛大鼠脊髓背角和背根神经节P2X4R表达上调,该变化可能与急性吗啡耐受和炎性痛的形成有关.

abstractsObjective To evaluate the changes in the expression of purinergic P2X4 receptor (P2X4R) in spinal cord dorsal horn and dorsal root ganglion in a rat model of acute morphine tolerance or inflammatory pain.Methods Thirty male SD rats were randomly divided into 3 groups:normal saline group (group NS,n =5);acute morphine tolerance group (group M,n =5) and inflammatory pain group (group F,n =20).Inflammatory pain was induced by subcutaneous injection of 4％ formalin 50 μl into the plantar surface of left hindpaw in group F.The animals received intrathecal morphine 10 μg ( 10 μl) once every 2 h for 6 times (T1-6) in group M,while the equal volume of normal saline was given instead in group NS.The rats were then sacrificed 2 h after the last time administration.Paw withdrawal latency (PWL) to a thermal nociceptive stimulus was measured at T1-6 in groups M and NS,or on day 4,7,10 and 14 after establishing the model of inflammatory pain in group F,The rats were sacrificed after measurement of PWL and spinal cord dorsal horn and dorsal root ganglion were removed to detect the expression of P2X4 R by immuno-histochemisty.Results Compared with the baseline value,PWL was significantly decreased on day 4-14 after intlammatory pain in group F,and PWL was significantly increased at T1-5,while no significant change was found at T6 in group M ( P ＞ 0.05).Compared with group NS,the expression of P2X4 R was up-regulated in group M,and the expression of P2X4 R was up-regulated on day 4 after inflammatory pain,peaked on day 7 after inflammatory pain,and then was down-regulated gradually on day 10 and 14 after inflammatory pain in group F ( P ＜ 0.01).Conclusion The expression of purinergic P2Y4 R is up-regulated in spinal cord dorsal horn and dorsal root ganglion in rats with acute morphine tolerance or inflammatory pain,and the change may be related to the development of acute morphine tolerance or inflammatory pain.