Effects and mechanisms of melatonin on immune responses in mice of different months  

褪黑素对不同月龄小鼠免疫反应的影响及其机制(英文)

作　　者：魏伟[1] 沈玉先[1] 戴敏[1] 陈群[1] 

机构地区：[1]安徽医科大学临床药理研究所

出　　处：《Acta Pharmacologica Sinica》2003年第7期719-723,727-728,共7页中国药理学报（英文版）

摘　　要：AIM: To study the effects and mechanisms of melatonin (MT) on immune responses in mice of different months. METHODS: Thymocyte proliferation and IL-2 activity were assayed by 3-(4,5-dimethylthiazol-2-yl) 2,5diphenyltetrazolium bromide (MTT) and activated mouse splenocyte proliferation methods, respectively; cAMP and methionine-enkephalin (met-Enk) level was determined by competitive protein binding assay and radioimmunoassay, respectively. RESULTS: The function of lymphocytes, obtained from BALB/c mice aged 6 and 11 months were decreased, which was restored by melatonin at the dose of 5 mg/kg or 30 mg/kg. In vitro, proliferation of lymphocytes in 11-month-old mice was decreased and cAMP level was increased. Melatonin (0.1 nmol/L or 1 μmol/L) had negative regulation to this. Forskolin (10 μmol/L) enhanced the cAMP level of lymphocytes in 2- and 11-month-old mice (P<0.01), which was antagonized partially by melatonin and this effect of melatonin was also abolished by pertussis toxin (1 mg/L) completely. Melatonn (1 μmol/L and 0.1 nmol/L) increased the content of met-Enk of lymphocytes in 2- and 11-month-old mice, respectively (P<0.01), which was blocked by nifedipine (1 μmol/L). CONCLUSION: Melatonin exerted an effect on immune responses in mice of different months, which might be mediated by G protein-AC-cAMP signal transduction pathway and regulation of met-Enk level.目的:研究褪黑素对不同月龄小鼠免疫反应的影响及其作用机制。方法:淋巴细胞增殖采用MTT法;IL-2活性检测 采用激活小鼠脾淋巴细胞增殖法;cAMP测定用竞争蛋白结合法;甲硫氨酸脑啡肽的测定采用放免法。结果:6月龄和11月龄BALB/c小鼠胸腺淋巴细胞增殖能力和IL-2的产生均降低,褪黑素(5mg/kg或30mg/kg,ig×7d)对上述指标有不同程度的改善作用,在体外,11月龄小鼠胸腺淋巴细胞增殖反应明显降低,而其产生的cAMP则明显升高,褪黑素(0.1nmol/L和1μmol/L)对此有反向调节作用,弗司可林(10μmol/L)(腺苷酸环化酶选择性激活剂)能够增强2月龄和11月龄BALB/c小鼠胸腺淋巴细胞内的cAMP水平,褪黑素可部分拮抗此作用,褪黑素的这一作用可被百日咳毒素(1mg/L)完全取消,同时发现褪黑素(1μmol/L和0.1nmol/L)能够明显提高2月龄和11月龄BALB/c小鼠胸腺淋巴细胞的甲硫氨酸脑啡肽含量,这一作用能被硝苯地平(1μmol/L)所阻断,提示褪黑素促进淋巴细胞甲硫氨酸脑啡肽释放可能由Ca^(2+)通道介导。结论:褪黑素对不同月龄小鼠具有免疫调节作用;G蛋白偶联的AC-cAMP信号转导通路和淋巴细胞甲硫氨酸脑啡肽的释放可能是褪黑素发挥免疫调节作用的重要机制之一。

关 键 词：MELATONIN IMMUNITY GTP-binding proteins cyclic AMP ENKEPHALINS 

分 类 号：R96[医药卫生—药理学]