Sleep and Chronobiology Laboratory, Department of Integrative Physiology, Center for Neuroscience, University of Colorado, Boulder, CO.
Sleep. 2013 Nov 1;36(11):1617-24. doi: 10.5665/sleep.3110.
Photic and non-photic stimuli have been shown to shift the phase of the human circadian clock. We examined how photic and non-photic time cues may be combined by the human circadian system by assessing the phase advancing effects of one evening dose of exogenous melatonin, alone and in combination with one session of morning bright light exposure.
Randomized placebo-controlled double-blind circadian protocol. The effects of four conditions, dim light (∼1.9 lux, ∼0.6 Watts/m(2))-placebo, dim light-melatonin (5 mg), bright light (∼3000 lux, ∼7 Watts/m(2))-placebo, and bright light-melatonin on circadian phase was assessed by the change in the salivary dim light melatonin onset (DLMO) prior to and following treatment under constant routine conditions. Melatonin or placebo was administered 5.75 h prior to habitual bedtime and 3 h of bright light exposure started 1 h prior to habitual wake time.
Sleep and chronobiology laboratory environment free of time cues.
Thirty-six healthy participants (18 females) aged 22 ± 4 y (mean ± SD).
Morning bright light combined with early evening exogenous melatonin induced a greater phase advance of the DLMO than either treatment alone. Bright light alone and melatonin alone induced similar phase advances.
Information from light and melatonin appear to be combined by the human circadian clock. The ability to combine circadian time cues has important implications for understanding fundamental physiological principles of the human circadian timing system. Knowledge of such principles is important for designing effective countermeasures for phase-shifting the human circadian clock to adapt to jet lag, shift work, and for designing effective treatments for circadian sleep-wakefulness disorders.
光照和非光照刺激已被证明可以改变人体生物钟的相位。我们通过评估外源性褪黑素（单独使用和与早晨强光暴露相结合使用）的一个晚上剂量对生物钟相位提前的影响，研究了人体生物钟系统如何结合光和非光时间线索。
随机安慰剂对照双盲生物钟方案。通过在恒常环境条件下治疗前后唾液褪黑素微光起始（DLMO）的变化，评估了四种条件下的生物钟相位效应：微光（约 1.9 勒克斯，约 0.6 瓦/平方米）-安慰剂、微光-褪黑素（5 毫克）、强光（约 3000 勒克斯，约 7 瓦/平方米）-安慰剂和强光-褪黑素。褪黑素或安慰剂在习惯性就寝时间前 5.75 小时给药，在习惯性醒来时间前 1 小时开始进行 3 小时的强光暴露。
无时间线索的睡眠和生物钟实验室环境。
36 名健康参与者（18 名女性）年龄 22 ± 4 岁（平均值 ± 标准差）。
早晨强光与傍晚外源性褪黑素联合使用比单独使用任何一种治疗方法都能更大程度地提前 DLMO 相位。单独使用强光和褪黑素诱导的相位提前相似。
来自光和褪黑素的信息似乎被人体生物钟结合。结合生物钟时间线索的能力对于理解人体昼夜节律计时系统的基本生理原理具有重要意义。了解这些原理对于设计有效的人体生物钟相位转移对策以适应时差、轮班工作以及设计有效的治疗昼夜节律睡眠-觉醒障碍的对策非常重要。
