Rimmele Ulrike, Spillmann Maria, Bärtschi Carmen, Wolf Oliver T, Weber Cora S, Ehlert Ulrike, Wirtz Petra H
Department of Clinical Psychology and Psychotherapy, Psychological Institute, University of Zürich, Binzmühlestrasse 14, Box 26, CH-8050 Zürich, Switzerland.
Psychopharmacology (Berl). 2009 Mar;202(4):663-72. doi: 10.1007/s00213-008-1344-z. Epub 2008 Oct 14.
Animal studies suggest that the pineal hormone melatonin influences basal stress hormone levels and dampens hormone reactivity to stress.
We investigated whether melatonin also has a suppressive effect on stress-induced catecholamine and cortisol release in humans. As stress hormones affect memory processing, we further examined a possible accompanying modulation of memory function.
Fifty healthy young men received a single oral dose of either 3 mg melatonin (n = 27) or placebo medication (n = 23). One hour later, they were exposed to a standardized psychosocial laboratory stressor (Trier Social Stress Test). During stress, subjects encoded objects distributed in the test room, for which memory was assessed a day later ("memory encoding under stress"). Fifteen minutes following stress, memory retrieval for words learnt the day before was tested ("memory retrieval after stress"). Plasma epinephrine and norepinephrine levels, salivary free cortisol levels and psychological responses (attention, wakefulness) were repeatedly measured before and after stress exposure.
Melatonin specifically enhanced recognition memory accuracy of objects encoded under stress (p < 0.001). In contrast, 15 min after stress, when cortisol levels were highest, retrieval of memories acquired the day before was not influenced by melatonin. Moreover, melatonin did not influence stress-induced elevation of catecholamine and cortisol levels which in turn did not correlate with the effects of melatonin on memory.
The findings point to a primary action of melatonin on central nervous stimulus processing under conditions of stress and possibly on memory consolidation and exclude any substantial suppressive action of the substance on hormonal stress responses.
动物研究表明，松果体激素褪黑素会影响基础应激激素水平，并减弱激素对应激的反应性。
我们研究了褪黑素是否也对人类应激诱导的儿茶酚胺和皮质醇释放具有抑制作用。由于应激激素会影响记忆处理过程，我们进一步研究了褪黑素对记忆功能可能产生的伴随性调节作用。
50名健康年轻男性单次口服3毫克褪黑素（n = 27）或安慰剂（n = 23）。1小时后，他们接受标准化的社会心理实验室应激源（特里尔社会应激测试）。在应激过程中，受试者对分布于测试房间内的物品进行编码，一天后评估对这些物品的记忆（“应激状态下的记忆编码”）。应激后15分钟，测试对前一天所学单词的记忆检索情况（“应激后的记忆检索”）。在应激暴露前后反复测量血浆肾上腺素和去甲肾上腺素水平、唾液游离皮质醇水平以及心理反应（注意力、清醒程度）。
褪黑素特异性地提高了应激状态下编码物品的识别记忆准确性（p < 0.001）。相比之下，应激后15分钟，即皮质醇水平最高时，褪黑素对前一天获取记忆的检索没有影响。此外，褪黑素不影响应激诱导的儿茶酚胺和皮质醇水平升高，而这反过来也与褪黑素对记忆的影响无关。
研究结果表明，褪黑素在应激条件下对中枢神经刺激处理可能具有主要作用，可能对记忆巩固也有作用，并且排除了该物质对激素应激反应有任何实质性抑制作用的可能性。
