腹侧被盖区注射M_5受体反义寡脱氧核苷酸对大鼠海洛因敏化的抑制作用  

Inhibition effect of M_5 muscarinic receptor antisense oligonucleotides microinjected into ventral tegmental area on heroin-induced locomotor sensitization in rats

作　　者：刘惠芬[1] 朱华强[1] 陈为升[1] 赖苗军[1] 周文华[1] 

机构地区：[1]宁波微循环与莨菪类药研究所宁波戒毒研究中心,浙江宁波315010

出　　处：《中国药理学与毒理学杂志》2009年第1期11-16,共6页Chinese Journal of Pharmacology and Toxicology

基　　金：国家自然科学基金项目(30670675);宁波市科技计划项目(2005C100007)~~

摘　　要：目的观察中脑腹侧被盖区(VTA)毒蕈碱受体亚型5(M5)在海洛因诱导大鼠行为敏化中的作用。方法Sprague-Dawley成年雄性大鼠sc海洛因0.25mg·kg-1·d-1,连续8d,制备海洛因敏化模型,每次给药后15min测定大鼠60min内的自主活动。之后停药10d,第18天VTA内微量注射M5受体反义(M5AS-ON)或正义寡脱氧核苷酸(M5S-ON)2μg。24h后大鼠sc海洛因0.25mg·kg-1激发,15min后测定大鼠60min内的自主活动。用免疫组化法检测大脑蓝斑核(LC)和杏仁核(LA)磷酸化cAMP反应元件结合蛋白(pCREB)表达水平。结果海洛因模型组戒断10d后大鼠自主活动较对照组显著增加,表明成功制备海洛因敏化模型;在海洛因激发前24hVTA微量注射M5AS-ON能抑制大鼠海洛因的行为敏化,而VTA中微量注射M5S-ON组与模型组无显著差异;同时,模型组大鼠脑内LC和LA区神经元pCREB免疫反应阳性表达增加,VTA中微量注射M5AS-ON能明显抑制LC及LA区神经元pCREB阳性表达的增加,而VTA中注射M5S-ON后大鼠LC和LA区神经元pCREB表达较海洛因敏化大鼠无显著差异。结论VTA内M5受体参与了海洛因的行为敏化,其作用机制可能与LC和LA神经元CREB蛋白的磷酸化改变有关。AIM To investigate the effect of muscarinic receptor subtype M5 in the ventral tegmental area （VTA） on the locomotor sensitization induced by heroin. METHODS Male Sprague-Dawley rats received a subcutaneous injection of heroin 0.25 mg·kg-1 once daily for consecutive 8 d and heroin sensitization model was set up. Locomotor activity was detected for 60 min at 15 rain after every administration. Then on the 18th day after 10 d intermission, M5 receptor antisense oligonucleotides （M5AS- ON ） or M5 receptor sense oligonucleotides （M5S-ON） 2μg was micro-injected into the rat＇s VTA through a stereotaxic surgery. After 24 h, rat locomotor sensitization was induced by repeated heroin 2.5 mg·kg^-1 administration, and at 15 rain after heroin administration locomotor activity was again detected for 60 min. The phospho-cAMP response element binding protein （pCREB） expression in the locus coeruleus （LC） and the lateral amygdaloid nucleus （LA） was assayed by immunohisto- chemistry. RESULTS After repeated heroin administration, all rats established locomotor sensitization, activity was significantly higher than control in the test day. Microinjection of M5AS-ON into the VTA 24 h prior to heroin challenge could partially inhibit locomotor sensitization induced by heroin. But there was no significant difference between M5S-ON and control group; the expression of pCREB-positive neurons in either the LC or the LA increased in model group compared with control. This increase could be inhibited by prior treatment with M5AS-ON into the VTA but not by M5S-ON. CONCLUSION M5 Receptor in the VTA is involved in heroin-induced locomotor sensitization, and the underling mechanism might be related to the regulation of pCREB expression in the LC and LA neurons.

关 键 词：海洛因 自主活动 受体 毒蕈碱 cAMP 反应元件结合蛋白 阿片相关性障碍 

分 类 号：R96[医药卫生—药理学]