Van Cauter E, Moreno-Reyes R, Akseki E, L'Hermite-Balériaux M, Hirschfeld U, Leproult R, Copinschi G
Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA.
Am J Physiol. 1998 Jul;275(1):E48-54. doi: 10.1152/ajpendo.1998.275.1.E48.
To investigate the adaptation of melatonin secretion to an abrupt time shift and the effects of sleep facilitation with a hypnotic, eight subjects were submitted to an 8-h advance shift achieved by advancing bedtimes from 2300-0700 to 1500-2300. Each subject participated in two studies (i.e., placebo and zolpidem). Each study included a baseline period with dim light during waking hours and 2300-0700 bedtimes in total darkness. Blood samples for determination of plasma melatonin were obtained at 20-min intervals for 68 h. Advanced exposure to sleep and darkness resulted in a nearly 2-h advance of melatonin onset, which appeared within 6 h after lights-out during the first shifted night, and an almost 1-h advance of the melatonin offset. No further adaptation occurred during the second shifted sleep period. Zolpidem had no beneficial effects on the adaptation of the melatonin profile. There was no relationship between sleep parameters and the magnitude of the melatonin shifts. Thus the overall advance of melatonin profiles was primarily achieved during the initial exposure to an 8-h period of darkness. The present data suggest that exposure to dark affects human circadian phase.
为研究褪黑素分泌对突然的时间变化的适应性以及催眠药促进睡眠的效果，8名受试者经历了8小时的提前移位，即就寝时间从23:00 - 07:00提前到15:00 - 23:00。每位受试者参与两项研究（即安慰剂和唑吡坦）。每项研究都包括一个基线期，清醒时处于昏暗灯光下，就寝时间为23:00 - 07:00，处于完全黑暗中。每隔20分钟采集一次血样以测定血浆褪黑素，共采集68小时。提前暴露于睡眠和黑暗环境导致褪黑素开始分泌时间提前近2小时，在第一个移位夜晚熄灯后6小时内出现，褪黑素分泌结束时间提前近1小时。在第二个移位睡眠期没有进一步的适应性变化。唑吡坦对褪黑素分泌模式的适应性没有有益影响。睡眠参数与褪黑素分泌变化幅度之间没有关系。因此，褪黑素分泌模式的总体提前主要是在最初暴露于8小时黑暗期时实现的。目前的数据表明，暴露于黑暗会影响人体昼夜节律相位。
