马来酸曲美布汀对束缚应激大鼠离体结肠平滑肌张力的调节作用机制

Regulation of activities of colonic smooth muscle in wrap restraint stress rats by trimebutine mealate

目的 研究曲美布汀对离体结肠平滑肌收缩及舒张运动的作用机制。方法 建立束缚应激诱发排便异常大鼠动物模型 ,制备离体结肠平滑肌环行肌及纵行肌肌条 ,应用张力换能器测定其肌张力。结果 束缚应激大鼠平滑肌肌条在基础状态时 ,曲美布汀可增加环行肌肌条张力 ,且随着浓度的递增平滑肌肌条张力有增加倾向。低于 10 -7g/ml曲美布汀可增加纵行肌肌条张力 ,但高于 10 -6g/ml时则降低肌条张力。曲美布汀可降低K+ 及乙酰胆碱作用下的束缚应激大鼠环行肌及纵行肌肌条张力 ,随着浓度的递增曲美布汀舒张平滑肌的作用有增加倾向。在Ca2 + 作用下 ,10 -8g/ml曲美布汀增加束缚应激大鼠纵行肌及环行肌肌条张力 ,但高于 10 -7g/ml时降低肌条的张力。结论 曲美布汀具有抑制和兴奋平滑肌双重作用 ,作用特点是调节平滑肌收缩与舒张运动 ,纠正肠管平滑肌运动异常。

Objective To investigate the mechanism of effect of trimebutine on the movement of colonic smooth muscle of wrap restrain stress (WRS) rats. Methods The tones of isolated longitudinal and circular muscle strips from colon in WRS rats were measured by transducer. Results In baseline condition, the tone of circular smooth muscle strips increased after trimebutine was added. But for longitudinal muscle strips, when the concentration of trimebutine was lower than 10 -7 g/ml, the tone increased; when the concentration of trimebutine was over 10 -6 g/ml, the tone decreased. In rich K + and acetycholine solution, trimebutine decreased the tone of smooth muscle strips. As its concentration increased, the tone tended to increase. In rich Ca 2+ solution, when the concentration of trimebutine was 10 -8 g/ml, the tone of smooth muscle strips increased; when the concentration of trimebutine was over 10 -7 g/ml, the tone decreased. Conclusion Trimebutine can either stimulate or inhibit spontaneous contractions of isolated both longitudinal and circular muscle strips of colon in WRS rats, depending on the previous contractile activity of muscle strips and the concentration of the drug and electrolytes in solution. Consequently, trimebutine may be used to relieve both atonic and irritable bowel syndrome.