褪黑素对豚鼠回肠体外吗啡依赖性的影响

Effect of Melatonin on Morphine Dependency in the Guinea-pig Ileum in vitro

目的 观察褪黑素 (MT)对豚鼠体外回肠吗啡依赖性的影响。 方法 以豚鼠体外回肠为实验对象 ,37℃孵育 3h,测定纳洛酮催发引起的戒断性收缩强度 ,作为产生依赖性的指标。 结果 豚鼠回肠标本用含吗啡(终浓度 4μmol/L )的 Krebs液孵育 3h,纳洛酮 (终浓度为 4μm ol/L )可催发戒断症状 (特异性收缩 ) ;MT(终浓度80 0μmol/L )单独孵育 3h,纳洛酮不会催发戒断性收缩 ;急性给 MT(终浓度分别为 1 0 0 ,2 0 0 ,4 0 0μmol/L )或预防性给 MT(终浓度分别为 2 5 ,1 0 0 ,4 0 0μm ol/L )均可剂量依赖性地减弱回肠戒断后的特异性收缩。 结论 MT可抑制回肠吗啡依赖性的产生且减弱回肠的吗啡依赖戒断性反应。

Objective To study the effect of melatonin(MT) on morphine dependence of the guinea|pig ileum in vitro. Methods The segments of the guinea|pig ileum(GPI) were suspended in organ chambers for measuring the withdrawal responses by naloxone. Results After GPI was incubated with morphine(4 μmol/L) at 37 ℃ for 3 h, the withdrawl contraction could be induced by naloxone; but treated with MT(800 μmol/L), the withdrawl contraction could not be occurred. After the segment of GPI was incubated with morphine(4 μmol/L) plus MT(25, 100, 400 μmol/L) at 37 ℃ for 3 h or with MT(100, 200, 400 μmol/L) at 37 ℃ for 0.5 h, the sensitivities for morphine were reduced significantly(P<0 01). {Conclution} MT could inhibit the development of morphine dependence in GPI and attenuate withdrawl contraction induced by nalaxone.