褪黑素镇痛作用的依赖性及免疫增强作用

Dependence of melatonin and its effect on immune function in mice

目的 观察褪黑素 (MT)的镇痛作用是否有耐受性和依赖性及其对免疫功能的影响。方法 依赖性观察采用小鼠竖尾实验和跳跃实验 ;免疫功能的检测采用免疫器官称重法、碳粒廓清实验及脾淋巴细胞增殖反应等。结果 MT 4 0mg/kg(qd× 7d ,ip)产生镇痛作用而无耐受现象 ,并能提高ConA诱导的小鼠脾淋巴细胞增殖反应 ;小鼠scMT 35 0mg/kg未出现竖尾现象 ;MT 35 0mg/kg (bid× 5d)后 ,用纳洛酮(5mg/kg)催瘾未出现跳跃现象 ,且对盐酸吗啡依赖小鼠的跳跃实验无明显影响 ;MT 35 0mg/kg (bid× 5d)后 ,脾、胸腺指数及碳粒廓清实验中K、α值高于溶媒组 ,提示MT能显著增加小鼠的非特异性免疫功能 ;盐酸吗啡 30mg/kg (bid× 5d)对小鼠的免疫功能有抑制作用。结论 MT镇痛作用无明显的耐受性及依赖性 。

Objective To investigate whether melatonin (MT) caused physical dependence and immunoregulation or not in mice. Methods Determination of the physical dependence by means of the tail erecting test and jumping test of mice.The immune function was evaluated by splenocytes proliferation, the weights of spleen and thymus, and clearance rate of charcoal particles (iv) in mice. Results No tolerance was observed in MT treated group at the dose of 40 mg/kg(ip,qd×7 d) which had analgesic effect in hot plate test. And MT enhanced splenocytes proliferation induced by ConA at the same dose. MT (350 mg/kg, sc) did not cause any tail erecting and jumping of mice treated with naloxone. The weights of spleen and thymus of mice were increased significantly by MT (350 mg/kg, bid) treatment for 5 days. Meanwhile, MT enhanced the clearance rate of charcoal particles(iv) in mice. Conclusion MT does not induce any tolerance and dependence when it exerts the analgesic effect, but it can enhance immune function.