中文摘要：

目的：探讨单次吗啡暴露对大鼠基底外侧杏仁核（BLA）和伏隔核核心部（NACc）吗啡敏感性差异的影响。方法：将18只SD大鼠随机均分成实验组（单次吗啡暴露）和对照组,分别在第1天皮下注射吗啡（5 mg/kg）或等容量生理盐水,注射过程均予以嗅觉条件刺激（茴香）。正常饲养到第8天,分别在乌拉坦麻醉下进行BLA、NACc电活动,以及体温、心电、呼吸肌肌电、皮肤电导的6通道同步记录,观察皮下注射5 mg/kg吗啡后BLA和NACc电活动以及外周生理指标的变化。结果：与对照组相比,不仅吗啡注射使实验组大鼠BLA和NACc的放电频率均明显升高（BLA：P〈0.01,NACc：P〈0.01）,而且NACc的放电频率又高于BLA（P〈0.05）。实验组BLA和NACc的基础放电频率呈高度正相关（rC=0.95,P=0.00）,与对照组的基础放电频率相关系数（rA=0.17,P=0.66）有显著差异（P〈0.05）,吗啡给药后实验组放电频率的相关系数（rD=0.57,P=0.11）也与对照组（rB=-0.59,P=0.10）有明显的差异（P〈0.05）。同时,在两组都观察到吗啡注射后体温出现一过性下降（P〈0.05）,实验组呼吸肌电平均周期明显下降（P〈0.05）,但其他检测的生理指标无显著性变化。结论：单次吗啡暴露不仅增强了大鼠BLA和NACc电活动的相关性,而且更明显地提高了NACc对再次注射吗啡的敏感性。

英文摘要：

AIM： To explore the distinctive effects of single morphine exposure on morphine-sensitivity of the basolateral amygdala（ BLA） and nucleus accumbens（ NACc） in rats. METHODS：Eighteen SD rats were randomly assigned to experimental group（ single morphine exposure） and control group. On day 1,morphine at 5 mg / kg or saline was subcutaneously injected in rats, conditioned with odour of anise,of experimental group or control group,respectively. On day 8,the extracellular recordings of the BLA and NACc electrical activities in the rat brain were conducted and physiological functions including body temperature, electrocardiography, electromyography and skin conductance were simultaneously monitored from the urethane-anesthetized rats of both experimental and control groups. The effects of morphine injection at 5 mg / kg on rats in both groups were observed. RESULTS：Compared with the control group,the firing rate of BLA and NACc in experimental group significantly increased（ BLA： P〈 0. 01,NACc： P〈 0. 01） after morphine injection,and the NACc was more responsive than BLA（ P〈 0. 05）. The basal firing rate of BLA and NACc in the experimental group was positively correlated（ rC= 0. 95; P = 0. 00） compared to that of the control group（ rA= 0. 17; P = 0. 66）.Moreover,after morphine injection,the correlation of BLA and NACc between two groups also displayed distinction（ Control group： rB=-0. 59,P = 0. 10;experimental group： rD= 0. 57,P = 0. 11）. Among the two groups,transient decline in body temperature was observed after morphine injection（ P〈 0. 05）,while decline in mean myoelectrical activity period only manifested in the experimental group（ P〈 0. 05） and the other monitored indexes remained unaltered. CONCLUSION： These results suggest morphine may affect the relationship between BLA and NACc after morphine single exposure, and NACc was more responsive than BLA.