Murakami N, Furukawa T, Yokawa T, Etoh T, Takahashi K
Jpn J Physiol. 1986;36(2):411-6. doi: 10.2170/jjphysiol.36.411.
Exposure to continuous light (LL) results in elongation of the free-running period of the rat circadian rhythm. However, the LL may not always mean constant intensity of light for the suprachiasmatic nucleus (SCN), since rats may regulate contrast of illumination by their eyelids which are closed during sleep phase. The removal of eyelids caused shortening of the free-running period or arrhythmicity under LL. In addition, implantation of carbachol--acetylcholine agonist--near the SCN also resulted in similar effects.
持续光照（LL）会导致大鼠昼夜节律的自由运转周期延长。然而，对于视交叉上核（SCN）而言，LL可能并不总是意味着恒定的光照强度，因为大鼠可能会通过在睡眠阶段闭合的眼睑来调节光照对比度。去除眼睑会导致在LL条件下自由运转周期缩短或出现节律异常。此外，在SCN附近植入卡巴胆碱（一种乙酰胆碱激动剂）也会产生类似的效果。
