Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor
Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor
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DOI：
10.1523/jneurosci.21-16-06405.2001
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发表时间：
2001-08
期刊：
影响因子：
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通讯作者：
G. Brainard;J. Hanifin;Jeffrey M. Greeson;B. Byrne;G. Glickman;E. Gerner;M. Rollag
中科院分区：
文献类型：
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作者：
G. Brainard;J. Hanifin;Jeffrey M. Greeson;B. Byrne;G. Glickman;E. Gerner;M. Rollag
人类眼睛中的感光色素将光转化为昼夜节律和神经内分泌调节，目前尚不清楚。这项研究的目的是建立光诱导的褪黑素抑制的作用谱，以帮助阐明调节人类松果体的眼部光感受器系统。受试者(女性37例，男性35例，平均年龄24.5±0.3岁)均为正常色觉受试者。全场单色光曝光发生在凌晨2：00到3：30之间，同时受试者的瞳孔被放大。对光照前后采集的血液样本进行褪黑素的定量检测。每个受试者都被测试了至少七种不同的同一波长的辐射，每次夜间曝光之间至少有一周的时间。夜间褪黑素抑制试验(n=627)，波长为420~600 nm。数据符合8条单变量、S形的流量-反应曲线(R2=0.81-0.95)。根据这些数据构建的作用光谱符合视蛋白模板(R2=0.91)，该模板确定446-477 nm是为调节褪黑素分泌提供昼夜输入的最有效的波长区域。结果表明，在人类中，单一的感光色素可能是褪黑素抑制的主要原因，其峰值吸收似乎与视杆细胞和视锥细胞感光色素不同。数据还表明，这种新的感光色素是以视黄醛为基础的。这些发现表明，在人眼中存在一种新的视光色素，它调节着昼夜节律的光接收。
The photopigment in the human eye that transduces light for circadian and neuroendocrine regulation, is unknown. The aim of this study was to establish an action spectrum for light-induced melatonin suppression that could help elucidate the ocular photoreceptor system for regulating the human pineal gland. Subjects (37 females, 35 males, mean age of 24.5 ± 0.3 years) were healthy and had normal color vision. Full-field, monochromatic light exposures took place between 2:00 and 3:30 A.M. while subjects' pupils were dilated. Blood samples collected before and after light exposures were quantified for melatonin. Each subject was tested with at least seven different irradiances of one wavelength with a minimum of 1 week between each nighttime exposure. Nighttime melatonin suppression tests (n = 627) were completed with wavelengths from 420 to 600 nm. The data were fit to eight univariant, sigmoidal fluence–response curves (R2 = 0.81–0.95). The action spectrum constructed from these data fit an opsin template (R2 = 0.91), which identifies 446–477 nm as the most potent wavelength region providing circadian input for regulating melatonin secretion. The results suggest that, in humans, a single photopigment may be primarily responsible for melatonin suppression, and its peak absorbance appears to be distinct from that of rod and cone cell photopigments for vision. The data also suggest that this new photopigment is retinaldehyde based. These findings suggest that there is a novel opsin photopigment in the human eye that mediates circadian photoreception.