Van Den Heuvel C J, Kennaway D J, Dawson D
Department of Obstetrics and Gynaecology, University of Adelaide, Adelaide, South Australia 5005.
Am J Physiol. 1998 Jul;275(1):E19-26. doi: 10.1152/ajpendo.1998.275.1.E19.
Daytime oral melatonin typically exerts soporific and thermoregulatory effects; however, it is not clear whether these effects reflect the normal physiological response to endogenous nocturnal melatonin production. We infused melatonin at doses that produced physiological and supraphysiological steady-state levels in 24 young adults during two daytime bed rest protocols. From 1000 to 1630, subjects were infused intravenously with saline or melatonin in counterbalanced order. Each group of eight subjects received melatonin (and saline) infusions at one dose rate: 0.04 microg . h-1 . kg body wt-1 (low), 0.08 microg . h-1 . kg-1 (medium), or 8.0 microg . h-1 . kg-1 (high). Low and medium melatonin infusions produced plasma and saliva levels within the normal nocturnal range observed in young adults. These levels were not associated with any changes in rectal, hand, forehead, or tympanic temperatures or with subjective sleepiness. High melatonin produced supraphysiological plasma and saliva levels and was associated with a significant attenuation in the daytime increase in rectal temperature, significantly increased hand temperature, and greater sleepiness. It is not yet clear whether the thermoregulatory and soporific effects of daytime supraphysiological melatonin administration are equivalent to the physiological responses to endogenous melatonin.
日间口服褪黑素通常会产生催眠和体温调节作用；然而，尚不清楚这些作用是否反映了对夜间内源性褪黑素分泌的正常生理反应。在两项日间卧床休息方案中，我们以能使24名年轻成年人产生生理和超生理稳态水平的剂量输注褪黑素。从10:00至16:30，受试者按平衡顺序静脉输注生理盐水或褪黑素。每组8名受试者以一种剂量速率接受褪黑素（和生理盐水）输注：0.04微克·小时-1·千克体重-1（低剂量）、0.08微克·小时-1·千克-1（中剂量）或8.0微克·小时-1·千克-1（高剂量）。低剂量和中剂量褪黑素输注产生的血浆和唾液水平在年轻成年人正常夜间范围内。这些水平与直肠、手部、额头或鼓膜温度的任何变化或主观嗜睡均无关。高剂量褪黑素产生超生理血浆和唾液水平，并与直肠温度日间升高的显著减弱、手部温度显著升高以及更强烈的嗜睡有关。目前尚不清楚日间给予超生理剂量褪黑素的体温调节和催眠作用是否等同于对内源性褪黑素的生理反应。
