Effects of Short and Long Nights on the Circadian Clock

短夜和长夜对生物钟的影响

• 批准号: 6678817
• 负责人: CHARMANE I EASTMAN
• 金额: $ 36.12万
• 依托单位: RUSH UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6678817
• 关键词: behavioral /social science research tag; biomarker; bioperiodicity; circadian rhythms; clinical research; human middle age (35-64); human subject; melatonin; photostimulus; seasons; sleep; sleep deprivation; young adult human (21-34)

DESCRIPTION (provided by applicant): It is widely recognized that humans in modern society do not get the sleep they need. This chronic sleep debt significantly degrades productivity, increases accident rates and has been linked to poor health and increased risk of death. Humans are exposed to a light dark (LD) cycle created by natural and artificial light alternating with sleep. Sleep duration determines the length of dark in the daily LD cycle. However, the effects of repeated short dark periods (short nights) on the human circadian system remain unknown. It has been proposed that mammals have a complex circadian pacemaker, consisting of an evening oscillator, that regulates the onset of melatonin secretion, and a morning oscillator, that regulates the offset of melatonin secretion. In short summer nights (longer photoperiods), the phase relationship between the evening and morning oscillators is decreased, which shortens the duration of the nocturnal melatonin profile, in turn regulating appropriate seasonal changes. Other animal work shows that the range and amplitude of the light phase response curve is decreased in short nights. We propose to investigate the effects of short and long nights on the human circadian system, by keeping subjects in bed, in the dark, for either 6 or 9 hours per night. We will determine if the duration of the melatonin rhythm in dim light compresses after a history of short nights, and expands after a history of long nights, thus revealing that the circadian pacemaker has a memory of the previous night length. We will also determine if a history of short nights reduces the phase shifting response to light. Our goal is to determine the extent to which the chronic sleep debt in modern society is altering the functioning of the human circadian system. This work has important implications for the sleep deprived general population and for jet travelers and night shift workers who must phase shift their circadian rhythms in order to adjust to phase shifts in their light/dark cycle.

描述(申请人提供)：人们普遍认为，现代社会中的人类得不到所需的睡眠。这种长期的睡眠债务严重降低了生产率，增加了事故率，并与健康状况不佳和死亡风险增加有关。人类暴露在由自然光和人造光与睡眠交替产生的明暗(LD)循环中。睡眠持续时间决定了每天LD周期中的黑暗长度。然而，反复的短暗时间(短夜)对人类昼夜节律系统的影响仍不清楚。哺乳动物有一个复杂的昼夜节律起搏器，由夜间振荡器和早晨振荡器组成，前者调节褪黑素分泌的开始，后者调节褪黑素分泌的偏移。在较短的夏夜(较长的光周期)，傍晚和早晨振荡器之间的相位关系减少，这缩短了夜间褪黑激素谱的持续时间，进而调节适当的季节变化。其他动物研究表明，在短夜里，光相位响应曲线的范围和幅度都会减小。 我们建议通过让受试者在床上、黑暗中每晚6小时或9小时来研究长夜和短夜对人类昼夜节律系统的影响。我们将确定褪黑激素节律在昏暗光线下的持续时间是否在短夜历史后压缩，而在长夜历史后扩大，从而揭示昼夜起搏器具有前一夜长度的记忆。我们还将确定短夜的历史是否会降低对光的相移反应。我们的目标是确定现代社会中长期的睡眠债务在多大程度上改变了人类昼夜节律系统的功能。这项工作对睡眠不足的普通人群以及喷气式飞机旅行者和夜班工作者具有重要的意义，他们必须相移他们的昼夜节律，以适应他们的明/暗周期的相移。