褪黑素对大鼠体温及活动度昼夜节律的影响

Effects of Melatonin on Circadian Rhythm of Temperature and Motor Activity in Rats

目的 了解外源性褪黑素对大鼠体温及活动度昼夜节律的影响及其可能的调节机制。方法 正常光照条件下 ,2 4h连续记录大鼠的体温及活动度的变化 ,以不同剂量褪黑素在不同的昼夜时间给药观察体温和活动度节律的变化。结果 大鼠的体温及活动度存在昼夜节律性 ,给药后昼夜节律性不消失 ;但体温振幅减小 ,中值降低。黑暗中期给药后 ,峰值位相显著延迟 ;活动度振幅增加 ,中值显著降低 ,峰值位相延迟。结论 外源性褪黑素不能使体温或活动度的昼夜节律消失 ,而只是改变昼夜节律的参数。褪黑素可分别调节体温和活动度的昼夜节律 ,但对活动度的调节作用更为明显。

Objective To investigate the effects of exogenous melatonin(MT) on circadian rhythm of temperature and motor activity in rats, to explore the mechanism of regulation on circadian rhythm. Methods Under normal light-dark (LD=12∶12) condition, the temperature and motor activity of rats were recorded continually for 24 h. MT was administered with different doses and in different time of the day. Results Circadian rhythms of temperature and motor activity of rats were found and were not abolished after the MT administration. MT treatment decreased the amplitude and the me dian of temperature. At CT18,MT delayed the acrophase of temperature evidently. MT increased the amplitude, reduced the mesor and delayed the acrophase of motor activity. Conclusion The circadian rhythms of the temperature and motor activity still exist with exogenous MT treatment. MT could function on the modulation of temperature and motor activity, especially the latter.