Hätönen T, Alila A, Laakso M L
Department of Physiology, University of Helsinki, Finland.
Brain Res. 1996 Feb 26;710(1-2):125-30. doi: 10.1016/0006-8993(95)01397-0.
Salivary melatonin levels were measured in 6 healthy volunteers in order to determine whether the phase shift caused by a single 60-min light pulse of 2000 lux might be inhibited by maintaining high melatonin concentration. In the control sessions, the samples were collected at 60-min intervals under lighting of < 10 lux from 18.00 to 11.00 h. In the light-exposure sessions, placebo or 0.5 mg melatonin was administered orally 60 min prior to the light pulse, timed at the rising phase of the melatonin synthesis. The after-light sessions, one day after the light exposure, were like the control sessions. The average delays of the melatonin half-rise and half-decline times were equal (about 0.7 h) in the placebo and melatonin replacement experiments. The maintenance of high melatonin levels during the light exposure did not counteract the influence of bright light on the melatonin rhythm. Thus, in the adjustment of the melatonin rhythm, light is a stronger regulator than melatonin itself.
为了确定维持高褪黑素浓度是否可能抑制由单次2000勒克斯60分钟光脉冲引起的相位偏移，对6名健康志愿者的唾液褪黑素水平进行了测量。在对照时段，于18:00至11:00在低于10勒克斯的光照下每隔60分钟采集一次样本。在光照暴露时段，在光脉冲前60分钟口服安慰剂或0.5毫克褪黑素，光脉冲时间设定在褪黑素合成的上升阶段。光照后时段在光照暴露一天后进行，与对照时段相同。在安慰剂和褪黑素替代实验中，褪黑素半上升和半下降时间的平均延迟相等（约0.7小时）。光照期间维持高褪黑素水平并不能抵消强光对褪黑素节律的影响。因此，在褪黑素节律的调节中，光比褪黑素本身是更强的调节因子。
