纳洛酮对吗啡成瘾大鼠海马脑电功率谱的影响

Effects of naloxone on the hippocampal electroencephalographic power spectrum in morphine-addicted rats

目的探讨阿片受体拮抗剂纳洛酮（naloxone，Nx）对吗啡成瘾大鼠海马脑电功率谱的影响。方法20只雄性Wistar大鼠，分为盐水组（n=10）和吗啡戒断组（rb=10），经8d生理盐水（1ml／kg）、盐酸吗啡（10mg／kg）交替皮下注射后建立躯体依赖模型，然后经盐酸纳洛酮（Nx，5mg／kg）腹腔注射观察其戒断反应；另取大鼠20只，分为盐水条件性位置偏爱（conditionedplacepreference，CPP）组（n=10）和吗啡CPP组（n=10），经8d盐水、吗啡交替注射训练建立CPP模型，然后经麻醉后注射Nx，记录Nx注射前后的背侧海马脑电，并分析功率谱数据。结果（1）与盐水戒断组比较，Nx使吗啡戒断组的戒断分数显著增加[（22．69±3．59）分VS（84．90±13．40）分，P〈0．01]；（2）吗啡CPP组测试期CPP分数[（80．69±14．96）分]相较自身基础值[（45．29±15．79）分]和盐水CPP组测试期分数[（41．84±12．47）分]均显著增加（P〈0．01）；（3）Nx使吗啡CPP组的海马EEG功率谱8频段功率[（81．80±30．91）mV2·Hz]较自身基线[（112．49±39．43）mV2·Hz）]、1频段功率[（25．35±11．20）mV2·Hz]较自身基线[（28．71±13．06）mV2·Hz]均可逆性的降低，差异具有统计学意义（P〈0．05）。结论Nx可降低吗啡成瘾大鼠海马脑电功率谱δ频段和γ频段功率。

Objective To investigate the effect of opiate receptor antagonist naloxone on the electroencephalographic （EEG） power spectrum in morphine-addicted rats. Methods 20 male adult Wistar rats were alternately injected with morphine （ Mf, 10 mg/kg, sc. ; Mf withdrawal （Mf-Wd） group, n= 10） or saline （ Sal, 1 ml/ kg, sc. ; Sal-Wd group, n= 10） for 8 days to establish Mf physical dependent model.Withdrawal scores were evaluated by naloxone-precipitated withdrawl signs （5 mg/kg, ip. ）. Another 20 rats were divided into Sal-CPP group and Mf-CPP group with 10 rats in each group.Rats in the sal-CPP group were injected with saline once a day for 8 days while rats in the Mf-CPP group were injected with saline and morphine alternatively once a day for 8 days.The EEG signals were recorded from their dorsal hippocampi before and after naloxone injection under anesthesia; and the EEG power data （1-100 Hz） were analyzed. Results （1） Compared with Sal-Wd group （22.69±3.59）,the Mf-Wd group showed a higher withdrawal scores after naloxone injection（ 84.90± 13.40, P〈0.01 ）. （2） The CPP scores of Mf-CPP rats （80.69± 14.96） were significantly higher than the baseline （45.29± 15.79） and the Sal-CPP rats （41.84±12.47; all P〈0.01）. （3）After naloxone injection,the EEG powers ofδ band and γ band of Mf-CPP rats decreased temporarily compared with their baseline （ δ band ： （ 81.80± 30.91 ） mV2 . Hz vs （ 112.49± 39.43 ） mV2 . Hz; y band：（25.35±11.20）mV2 . Hzvs （28.71±13.06）mV2 . Hz; allP〈0.05）. Conclusion Opiate receptor antagonist naloxone can decrease the hippocampal EEG powers of δ band and γ band in Mr-addicted rats.