Broadway J, Arendt J, Folkard S
Department of Biochemistry, University of Surrey, Guildford, U.K.
Neurosci Lett. 1987 Aug 18;79(1-2):185-9. doi: 10.1016/0304-3940(87)90694-x.
In most species daily and seasonal changes in the light-dark cycle are the most important synchronisers (zeitgebers) of daily and seasonal rhythms. In humans only bright light (2500 lux) appears to be an effective circadian zeitgeber. Seasonal effects of light on human physiology have not been investigated. We have exploited the low intensity illumination of the Antarctic winter to investigate the effects of bright- or dim-light treatment for an hour in the morning and in the evening (a 'skeleton' 12.5-h day) for 6 weeks on the plasma melatonin rhythm, together with mood and a number of behavioural variables. In parallel seasonal changes in melatonin were observed. Melatonin is known to convey daylength information in photoperiodic seasonal breeders through characteristics of its night-time secretion profile. Bright-, but not dim-, light treatment in winter induced a marked phase advance of the melatonin rhythm, similar to that found in the summer, without marked effect on the other variables. Thus at least one human seasonal change appears to be light-dependent.
在大多数物种中，昼夜周期的每日和季节性变化是每日和季节性节律最重要的同步器（授时因子）。在人类中，只有强光（2500勒克斯）似乎是一种有效的昼夜节律授时因子。光对人体生理的季节性影响尚未得到研究。我们利用南极冬季的低强度光照，研究了在早晨和晚上进行一小时强光或弱光治疗（一个“骨架”式的12.5小时白天），持续6周，对血浆褪黑素节律以及情绪和一些行为变量的影响。同时观察到了褪黑素的季节性变化。已知褪黑素通过其夜间分泌特征在光周期季节性繁殖动物中传递日照长度信息。冬季的强光而非弱光治疗使褪黑素节律显著提前，类似于夏季观察到的情况，对其他变量没有显著影响。因此，至少一种人类季节性变化似乎与光有关。
