脊髓G蛋白表达在代谢型谷氨酸5受体参与吗啡耐受形成中的作用  

THE ROLE OF G PROTEIN EXPRESSION IN THE PARTICIPATION OF METABOTROPIC GLUTAMATE RECEPTOR 5 IN MORPHINE TOLERANCE

作　　者：陈默曦[1] 许涛[1] 周全红[1] 薛瑛[1] 江伟[1] 

机构地区：[1]上海交通大学附属第六人民医院麻醉科,上海200233

出　　处：《中国疼痛医学杂志》2012年第6期367-371,共5页Chinese Journal of Pain Medicine

基　　金：国家自然科学基金项目资助(30972850)

摘　　要：目的：研究鞘内注射代谢型谷氨酸5受体（metabotropic glutamate receptor 5,mGluR5）反义寡聚脱氧核苷酸（oligodeoxynucleotide,ODN）时大鼠吗啡耐受发生情况及其对脊髓内G蛋白各亚型表达的影响。方法：将48只雄性SD大鼠随机分为6组：对照组（S组,n=14）,反义链组（ANT组,n=6）,错义链组（MIS组,n=6）,吗啡耐受组（M组,n=6）,反义链吗啡合用组（AM组,n=8）和错义链吗啡合用组（MM组,n=8）。采用鞘内给药方式注射寡聚核苷酸、吗啡和生理盐水。以5μl含30 nM的寡聚核苷酸（ANT组,MIS组,AM组和MM组）或0.9%生理盐水（S组和M组）每日给药2次,连续5天。于第6天取6只S组及ANT组和MIS组大鼠L4/5脊髓行real-time PCR,观察其mGluR5的mRNA表达。其余大鼠于第6天起连续3天每日给吗啡2次,每次15μg,S组以5μl0.9%生理盐水代替。给药后以热板试验测定其热痛阈,以缩爪阈值作为机械痛阈指标,并计算最大效应分数（maximum percent effect,MPE）进行比较。采用免疫印迹（western blot）方法检测并比较各组L4/5脊髓中G蛋白各亚型（Gαi,Gαo,Gαq和Gβ）的表达。结果：ANT组中mGluR5含量比S组下降48.2%（P〈0.05）,MIS组无此效果。M组和MM组大鼠MPE%在第8天与S组比较无统计学差异（P〉0.05）,AM组大鼠MPE%在第8天仍高于S组,有统计学意义（P〈0.05）。AM组大鼠MPE%在第7~8天即显著高于M组（P〈0.05）。第9天M组和MM组大鼠Gαi,Gαo,Gαq和Gβ的蛋白表达量显著高于S组（P〈0.05）。而AM组大鼠G蛋白各亚型表达量均与S组无显著性差异（P〉0.05）,与M组相比显著下调（P〈0.05）。结论：大鼠吗啡耐受发生时,大鼠腰段脊髓G蛋白各亚型表达均明显升高。鞘内注射mGluR5反义寡聚脱氧核苷酸能显著抑制大鼠吗啡耐受的发生并抑制G蛋白各亚型的表达升高。Objective： To investigate the role of intrathecal injection of metabotropic glutamate receptor 5（mGluR5） antisense oligodeoxynucleotide（ODN） on the occurrence of morphine tolerance and expressions of spinal G proteins in rats.Methods： Forty-eight male Sprague-Dawley rats were randomly divided into six groups： control group（S group,n = 14）,antisense ODN group（ANT group,n = 6）,mismatch ODN group（MIS group,n = 6）,morphine tolerance group（M group,n = 8）,antisense ODN plus morphine group（AM group,n = 8） and mismatch ODN plus morphine group（MM group,n = 8）.Rats in ANT group,MIS group,AM group and MM group received 5 μl of intrathecal 30 nM ODN twice a day for 5 days.Rats in S and M groups were received 5 μl of 0.9% saline twice a day for 5 days.On day 6,real-time PCR was used to investigate the mRNA of mGluR5 in S group,ANT group and MIS group.From day 6,15 μg morphine was added twice a day in M group,AM group and MM group.Rats in S group received 5 μl of 0.9% saline instead of any drugs.Hot-plate test and paw pressure test were used to assess nociception and maximum percent effect（MPE） was measured.The expressions of G proteins（Gαi,Gαo,Gαq and Gβ） were detected by western blot.Results： Compared with S group,mGluR5 was reduced by 48.2% in ANT group（P 0.05）.MPE% of AM group on day 8 was still higher than S group（P 0.05）.The expression of G protein of AM group was decreased than M group.Conclusion： Intrathecal injection of mGluR5 antisense ODN can inhibit the occurrence of morphine tolerance,and reduce the up-regulated G protein（Gαi,Gαo,Gαq and Gβ） expression in the rat spinal cord which would happen when tolerance occurs.

关 键 词：吗啡耐受 寡聚脱氧核苷酸 代谢型谷氨酸受体5 G蛋白 

分 类 号：R402[医药卫生—临床医学]