SENSITIVITY OF THE HUMAN CIRCADIAN PACEMAKER TO MODERATELY BRIGHT LIGHT
SENSITIVITY OF THE HUMAN CIRCADIAN PACEMAKER TO MODERATELY BRIGHT LIGHT
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DOI：
10.1177/074873049400900311
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发表时间：
1994-12-01
影响因子：
3.5
通讯作者：
CZEISLER, CA
中科院分区：
文献类型：
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作者：
BOIVIN, DB;DUFFY, JF;CZEISLER, CA
本研究的目的是评估人类昼夜节律起搏器对中等亮度光重置效应的敏感性（类似于1260勒克斯），并通过与经历相同行为操作但具有类似时间暴露于黑暗而不是光的对照组受试者进行比较来评估这种光暴露的直接影响。在两组不同的年轻健康男性中，使用恒定常规技术，在两个连续系列的三个5小时暴露于类似于1260勒克斯或黑暗（类似于0.03勒克斯）之前和之后，暴露于光（类似于10-15勒克斯）。在初始拟合的内源性温度最低值后1.5小时和与新安排的睡眠事件中点相对的12小时，集中光照或黑暗暴露，以诱导光照受试者的相位提前。内源性昼夜节律起搏器的相位通过双谐波回归模型从恒定程序期间每分钟记录的核心体温进行评估。在每次排尿时测量尿量，每20分钟测量一次主观警觉性，每小时测量一次认知能力，治疗组在每次系列光照后的内源性昼夜节律时相明显早于对照组（重复测量的双向方差分析：F = 67.91，p = 0.0001）。对尿产量、主观警觉性和认知能力得分的昼夜节律曲线的分析显示，所有变量与内源性昼夜节律温度最低值保持稳定的时间关系，这表明这些节律在同一方向上发生了等量的变化。尽管有类似的行为时间表，包括卧床休息/睡眠和社会接触的时间，控制对象的昼夜温度节律在昏暗的光线条件下自由奔跑，表明适度明亮的光线对治疗组中的人类昼夜节律起搏器产生直接的生物学效应。本研究还表明，类似于1260勒克斯的光（其强度显著低于先前实验中使用的类似于7000- 12，000勒克斯的光）产生内源性昼夜节律的稳健相位推进，这已被证明是昼夜节律起搏器输出的准确标记（Czeisler等人，1989年）。这些结果支持了这样的假设，即光对人类昼夜节律起搏器的相移效应与照度水平具有强烈的非线性关系，使得尽管光强度显著降低，但它仍被保留。
The aim of the present study was to evaluate the sensitivity of the human circadian pacemaker to the resetting effect of moderately bright light (similar to 1260 lux), and to assess the direct effect of such light exposure by comparison to a control group of subjects undergoing the same behavioral manipulations but with a similarly timed exposure to darkness instead of light.Endogenous circadian phase and amplitude were assessed in dim light (similar to 10-15 lux) before and after two consecutive series of three 5-hr exposures to similar to 1260 lux or to darkness (similar to 0.03 lux) in two different groups of young healthy men, using the constant-routine technique. The light or darkness exposure was centered 1.5 hr after the initial fitted endogenous temperature minimum and 12 hr opposite the newly scheduled midpoint of the sleep episode, in order to induce a phase advance in the light-exposed subjects. The phase of the endogenous circadian pacemaker was assessed by a dual-harmonic regression model from core body temperature recorded every minute during constant routines. Urinary volume was measured at each micturition, subjective alertness every 20 min, and cognitive performance hourly.The endogenous circadian phase shifted to a significantly earlier time after each series of light exposures in the treatment group than it did in the control group (two-way analysis of variance for repeated measures: F = 67.91, p = 0.0001). The analysis of circadian curves of urine production, subjective alertness, and cognitive performance scores revealed that all variables maintained stable temporal relationships with the endogenous circadian temperature minimum-an indication that these rhythms shifted in the same direction and by an equivalent amount. Despite comparable behavioral schedules, including the timing of bedrest/sleep and social contacts, circadian temperature rhythm of control subjects free-ran under dim light conditions, indicating that moderately bright light exerted a direct biological effect on the human circadian pacemaker in the treatment group. The present study also demonstrated that light of similar to 1260 lux (which is of substantially lower intensity that the similar to 7000-12,000 lux used in prior experiments) produces robust phase advances of the endogenous circadian temperature rhythm, which has been shown to be an accurate marker of the output of the circadian pacemaker (Czeisler et al., 1989). These results support the hypothesis that the phase-shifting effect of light on the human circadian pacemaker has a strongly nonlinear relationship to illuminance levels, such that it is preserved despite marked reductions in light intensity.