【摘要】 目的 观察在不同剂量乙醇作用下大鼠下丘脑和脊髓神经细胞P物质的表达情况和扫描电子显微镜（SEM）下神经细胞的形态学变化，探讨乙醇作用下大鼠行为学改变的相关机制。 方法 通过福尔马林实验观察大鼠在不同剂量乙醇及时间作用下行为学的改变；采用免疫组织化学技术检测不同剂量乙醇作用下大鼠脊髓和下丘脑神经细胞中P物质的表达，通过扫描电子显微镜观察神经细胞的形态学变化。 结果 乙醇灌胃后0～2 h大鼠舔足次数有不同程度的变化，组间比较差异有统计学意义（Plt;0.05），灌胃2 h大鼠下丘脑和脊髓P物质表达程度与乙醇剂量有相关关系，扫描电子显微镜下各组大鼠的神经细胞形态学变化显著。 结论 急性乙醇中毒可引起大鼠对疼痛反应的变化，其程度与乙醇剂量和作用时间有关，大鼠下丘脑和脊髓神经细胞中P物质的表达强度与乙醇剂量和作用时间有关。【Abstract】 Objective To observe the expression of substance P(SP)in the hypothalamus and spinal cord nerve cells of rats with different concentrations of ethanol, and to observe the morphological changes of nerve cells by scanning electron microscopic(SEM) for elucidating the mechanism of ethological changes effected with ethanol. Methods Ethological changes were detected through the formalin test; SP expressions in the hypothalamus and the spinal cord were evaluated with immunohistochemistry technology, and the morphological changes of nerve cells were observed by SEM. Results The frequency of licking foot changed when the rats were gavaged with different concentrations of ethanol among zero to two hours, the difference between two groups was statistical signifcant (Plt;0.05). The expression level of SP and the morphological changes of nerve cells in hypothalamus and spinal cord had relationship with the ethanol concentration. Conclusions Acute alcoholism could cause pain dysfunction in rats. The frequency of licking foot of rats is correlated to the role of the time closely. The expression intensity of SP in the hypothalamus and the spinal cord nerve cells are correlated to the concentration of ethanol closely.