Podolin P L, Rollag M D, Brainard G C
Endocrinology. 1987 Jul;121(1):266-70. doi: 10.1210/endo-121-1-266.
It has recently been shown that wavelengths in the near-UV range (UV-A, 320-400 nm) are capable of influencing pineal melatonin content in the hamster. The purpose of this study was to compare the capacities of monochromatic visible and UV radiation for suppressing nocturnal pineal melatonin. Groups of male Syrian hamsters adapted to a 14-h light, 10-h dark cycle (lights on, 1700-0700 h) were exposed to irradiances of 500 or 360 nm light for 5 min during their dark phase. Both wavelengths suppressed pineal melatonin in a dose-related manner. The resultant fluence-response curves were similar in shape, although their corresponding threshold irradiances were markedly different. The calculated ED50 values for 500 and 360 nm light were 0.022 microW/cm2 (1.66 X 10(13) photons/cm2) and 0.306 microW/cm2 (1.66 X 10(14) photons/cm2), respectively. These data show that the induction of a 50% depression of pineal melatonin requires 10 times the number of 360-nm photons compared to 500-nm photons at the level of the cornea. Despite this difference in sensitivity to wavelength, environmental irradiances of UV-A are well above the threshold for melatonin suppression in the hamster. These results thus demonstrate the importance of considering UV-A, in addition to the visible wavelengths, in the regulation of hamster pineal physiology.
最近研究表明，近紫外光范围（UV-A，320 - 400纳米）的波长能够影响仓鼠松果体褪黑素的含量。本研究的目的是比较单色可见光和紫外线辐射抑制夜间松果体褪黑素的能力。将适应14小时光照、10小时黑暗周期（光照时间为17:00 - 07:00）的雄性叙利亚仓鼠分组，在黑暗期给予它们500或360纳米波长的光照射5分钟。两种波长的光均以剂量相关的方式抑制松果体褪黑素。尽管它们相应的阈值辐照度明显不同，但得到的剂量-反应曲线形状相似。500纳米和360纳米光的计算ED50值分别为0.022微瓦/平方厘米（1.66×10¹³个光子/平方厘米）和0.306微瓦/平方厘米（1.66×10¹⁴个光子/平方厘米）。这些数据表明，在角膜水平上，诱导松果体褪黑素降低50%，与500纳米光子相比，360纳米光子所需数量要多10倍。尽管对波长的敏感性存在差异，但UV-A的环境辐照度远高于仓鼠褪黑素抑制的阈值。因此，这些结果证明了在调节仓鼠松果体生理过程中，除了可见光波长外，考虑UV-A的重要性。
