目的观察内吗啡肽(EM)及μ阿片受体mRNA在“泻剂结肠”大鼠结肠神经丛表达和分布,以进一步明确慢传输性便秘(slow tran-sit constipation,STC)的发病机制和病理生理变化。方法建立“泻剂结肠”大鼠动物模型,应用免疫组化法和图像分析系统观察结肠神经丛内EM免疫反应阳性细胞分布和数量变化,用原位杂交法测定结肠中μ阿片受体mRNA的表达水平。结果与对照组相比,泻剂组结肠肌间神经丛EM阳性细胞数量明显增多(10.319±1.612vs7.683±1.359,P<0.05),μ阿片受体mRNA的表达增强(0.3034±0.0651vs0.1823±0.0150,P<0.01),远端结肠尤甚。结论EM及其受体参与结肠动力的调控,肠神经递质及受体的异常可能是STC发病的一种重要因素,提示长期应用刺激性泻剂可损伤肠神经系统,导致肠动力异常,加速STC的病理生理变化。 Objective To observe the expression and distribution of endomorphin (EM) and μ opioid receptor mRNA in the colon of the “cathartic colon” rats to further clarify the pathogenesis of slow tran-sit constipation (STC) And pathophysiological changes. Methods The animal model of “laxative colon” was established. Immunohistochemistry and image analysis system were used to observe the distribution and quantity of EM immunoreactive cells in the colonic plexus. The μ opioid receptor in the colon was determined by in situ hybridization mRNA expression level. Results Compared with the control group, the number of EM positive cells in colonic myenteric plexus of laxative group was significantly increased (10.319 ± 1.612 vs 7.683 ± 1.359, P <0.05) and mu opioid receptor mRNA was increased (0.3034 ± 0.0651 vs0. 1823 ± 0.0150, P <0.01), especially in the distal colon. Conclusions EM and its receptors are involved in the regulation of colonic motility, and the abnormality of the intestinal neurotransmitter and receptor may be an important factor in the pathogenesis of STC. It suggests that long-term use of stimulant laxatives can damage the enteric nervous system, lead to abnormal intestinal motility, accelerate STC pathophysiological changes.