Waldhauser F, Kovács J, Reiter E
Department of Pediatrics, University Hospital of Vienna, Austria.
Exp Gerontol. 1998 Nov-Dec;33(7-8):759-72. doi: 10.1016/s0531-5565(98)00054-0.
Prior to three months of age there is little melatonin (MLT) secretion in humans. MLT production then commences, becomes circadian, and reaches its highest nocturnal blood levels between the ages of one to three years. During the remainder of childhood, nocturnal peak levels drop progressively by 80%. In adults, these levels show an additional drop of some 10%, mainly during senescence. The large drop in serum MLT during childhood is probably the result of the increase in size of the human body, despite a constant MLT production after infancy. The additional decline of MLT with higher age may be due to a yet unidentified physiological mechanism accompanying senescence. The biological significance of these MLT alterations remains unknown. Since the discovery of MLT, an immediate sedative action of this hormone has been known. A number of recent studies have demonstrated that MLT indeed exerts a sleep-promoting action by accelerating sleep initiation, improving sleep maintenance, and marginally altering sleep architecture. The potential of MLT in the treatment of insomnia is being explored, and the results are promising. Although in most of these studies pharmacological dosages of MLT have been used, preliminary data suggest that similar effects can also be achieved by physiological hormone concentrations. The latter observation raises the question of whether MLT might be involved in the physiological control of sleep.
在三个月大之前，人类体内几乎没有褪黑素（MLT）分泌。之后MLT开始产生，呈现昼夜节律性，在1至3岁之间达到夜间血液中的最高水平。在童年的其余时间里，夜间峰值水平逐渐下降80%。在成年人中，这些水平又会额外下降约10%，主要发生在衰老过程中。童年时期血清MLT的大幅下降可能是由于人体尺寸增加，尽管婴儿期后MLT的产生量保持恒定。随着年龄增长MLT的进一步下降可能是由于衰老过程中一种尚未明确的生理机制。这些MLT变化的生物学意义仍然未知。自从发现MLT以来，人们就知道这种激素具有直接的镇静作用。最近的一些研究表明，MLT确实通过加速入睡、改善睡眠维持以及轻微改变睡眠结构来发挥促进睡眠的作用。MLT在治疗失眠方面的潜力正在被探索，结果很有希望。尽管在大多数这些研究中使用的是MLT的药理剂量，但初步数据表明，生理激素浓度也能产生类似的效果。后一观察结果引发了一个问题，即MLT是否可能参与睡眠的生理控制。
