四氢原小檗碱对吗啡依赖大鼠脑内相关核团多巴胺D_1、D_2受体基因表达的影响

Effects of tetrahydroprotoberberines on expression of dopamine system related genes in morphine dependent rats

目的 研究吗啡依赖对大鼠中脑边缘多巴胺(DA)系统内相关核团DA受体的影响及四氢原小檗碱(THPB)对其的效应。方法 将30只SD大鼠随机分为5组,每组6只。正常对照组始终给予等量生理盐水腹腔注射,4组建立吗啡依赖模型。以5 mg/kg开始腹腔注射,2次/d,每次递增5 mg,一直增至第10天每次50 mg/kg;第11天起对其中的两组分别注射生理盐水12 d(Mor+NS12组)和30 d(Mor+NS30组),另两组分别注射30 mg/kg THPB 12 d(Mor+THPB 12组)和30 d(Mor+THPB 30组)。分别测定中脑腹侧被盖区(VTA)等脑结构酪氨酸单氧化酶(TM)免疫阳性神经元的平均吸光度(A)值、D1R mRNA和D2R mRNA水平。结果 与正常对照组相比,Mor+NS组大鼠VTA的TM表达持续增高(P<0.01)。治疗12 d时,Mor+NS12组D1R mRNA在伏隔核、杏仁核、尾壳核、前额叶皮质的含量和D3R mRNA在VTA、尾壳核、伏隔核的含量均低于正常对照组(P<0.01),而Mor+THPB12组在伏隔核、杏仁核、尾壳核的D1R mRNA含量和VTA、尾壳核的D2R mRNA的含量与正常对照组的差异无显著性。治疗30 d时,Mor+NS30组D1R mRNA(除杏仁核外)和D2R mRNA在各脑区的含量仍低于正常对照组(P<0.01);而Mor+THPB30组D1R mRNA除前额叶皮质外的含量和D2R mRNA的含量已至正常水平。结论

Objective To explore the effects of tetrahydroprotoberberines (THPB) on the expression of dopamine ( DA ) system related genes in some brain regions of morphine dependent rats. Methods Thirty rats were randomly assigned into five groups. The rats in control group were injected with saline all the time. The four groups were intraperitoneally injected with increasing dose of morphine for 10 days to establish morphine dependence model. After abstinence, two groups were injected with saline for 12 or 30 days, while other two treated with THPB for 12 or 30 days respectively. Following the procedure, all rats were anesthetized and infused with poly-formaldehyde. Tyrosine 3-monooxygenase (TM) was detected by immune-chemical reaction with avidin-biotin peroxidase complex ( ABC) method, and D, receptor (D1R), D2 receptor (D2R) mRNA were detected with in situ hybridization. Results Level of TM in ventral tegmental area ( VTA) region of morphine dependent rats was higher than that of control ( P < 0. 05). THPB could remarkably inhibit the increase, which exhibited distinct difference with the saline treatment groups (P < 0. 05). Expression of D1 R mRNA in nucleus accumbens septi, amygdalae, caudatum putamen, prefrontal cortex and D2R mRNA in VTA, caudatum putamen and nucleus accumbens septi were significantly decreased than that of control. Both of them failed to return to normal at the 30th day after abstinence. The D2R mRNA expression in administration THPB group, although decreased in the 12th day in VTA, was no significant difference than that of control group in other brain regions and different time. Conclusion THPB could remarkably inhibit the excessive expression of TM in VTA region, promote D1 R mRNA and D2R mRNA expression in brain and accelerate DA system functional recovery after morphine abstinence, and these findings provide evidence for the prevention and detoxification of opiate addiction.