Reiter R J, Joshi B N, Heinzeller T, Nürnberger F
Endocrinology. 1986 May;118(5):1906-9. doi: 10.1210/endo-118-5-1906.
Adult male Syrian hamsters maintained under 6-h light, 18-h dark cycles (lights out daily from 1200-0600 h) were exposed to either 1 or 5 sec light either 8 h (at 2000 h) or 12 h (at 2400 h) into the dark phase. The light had an irradiance of 32,000 microW/cm2. With both light pulse durations and at both times, melatonin levels were depressed to daytime values 30 min after the onset of the light pulse. Whereas pineal melatonin production eventually increased to high nighttime values in hamsters exposed to 1 sec light at either 2000 or 2400 h and in animals receiving a 5-sec light pulse at 2000 h, when the 5-sec light occurred at 2400 h, pineal melatonin levels remained low for the remainder of the night. Thus, both the placement and the duration of light exposure appear to be important in determining the ability of light to depress melatonin production in the Syrian hamster.
将成年雄性叙利亚仓鼠饲养在6小时光照、18小时黑暗的周期中（每天12:00至06:00熄灯），在黑暗期8小时（20:00）或12小时（24:00）时，让它们暴露于1秒或5秒的光照下。光照强度为32,000微瓦/平方厘米。在两种光照持续时间以及两个时间点，光照脉冲开始后30分钟，褪黑素水平均降至白天的值。在20:00或24:00接受1秒光照的仓鼠以及在20:00接受5秒光照脉冲的动物中，松果体褪黑素的分泌最终会增加到夜间的高水平，而当在24:00出现5秒光照时，松果体褪黑素水平在夜间剩余时间内仍保持较低。因此，光照的时间点和持续时间似乎对于决定光照抑制叙利亚仓鼠褪黑素分泌的能力都很重要。
