褪黑素是松果体合成的一种激素，它的分泌有着明显的昼夜节律和季节规律。褪黑素不仅与睡眠、衰老、免疫关系密切，而且对疼痛的调节也发挥着极其重要的作用。大量研究表明，在急性痛、炎性痛及神经病理性疼痛等多种类型的疼痛中，褪黑素能够预防、减轻乃至逆转伤害性疼痛。关于褪黑素的具体作用机制目前并不是很清楚，但已有的研究认为可能与膜信号通道和核信号途径相关，特别是与中枢神经系统的褪黑素受体和阿片受体关系密切。从而，褪黑素受体可能成为镇痛作用的新靶点，通过褪黑素受体的激活到达有效治疗疼痛的目的。本综述提供了褪黑素作为一种潜在的镇痛药在动物实验和临床研究中的一系列有用的依据。

Melatonin is a hormone synthesized principally in the pineal gland. Its secretion is closely related to the circadian rhythm and season rhythm. Melatonin is no only closely associated with sleep, ageing, immunity, but also play a vital role in pain modulation. It has been shown that melatonin can prevent, reduce and reverse nociceptive pain in different models of pain such as acute pain, inflammatory pain, neuropathic pain, et al. The mechanisms of the melatonin analgesic effects are not fully understood. It may exert its actions via membrane-signaling pathway, and melatonin receptors and opioid receptors in the central nervous system may be particularly important to the effects of melatonin. Thus, melatonin receptor will become an attractive target in pain treatment, and it may be a novel strategy to generate analgesic effects through activating melatonin receptor. In this review, we provide a lot of evidence available from animal experiments and clinical studies to melatonin as a potential analgesic.

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