Suzuki Rie, Rygh Lars J, Dickenson Anthony H
Department of Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
Trends Pharmacol Sci. 2004 Dec;25(12):613-7. doi: 10.1016/j.tips.2004.10.002.
The identification of opioid systems led to much of the early work on pain pharmacology being based on understanding inhibitory mechanisms of analgesia. However, hyperalgesia and allodynia are common clinical symptoms and therefore hyperexcitability must be a major component of pain. Thus, the emphasis of current research into pain has shifted to understanding excitatory pathways that underlie neuronal sensitization and potentiation. Although much evidence supports the presence of descending inhibitory mechanisms of pain, reports of facilitatory pathways from the brainstem have been scarce. In this article, we review evidence for facilitatory 5-HT pathways that link spinal cord and brainstem areas involved in mood and emotions. Because pain encompasses affective aspects, we suggest that these 5-HT pathways and other circuits are important in determining the levels of pain, the outcome of drug treatments and provide a mechanism whereby emotions can alter pain perception.
阿片系统的发现使得早期许多疼痛药理学研究工作都基于对镇痛抑制机制的理解。然而，痛觉过敏和异常性疼痛是常见的临床症状，因此神经元兴奋性过高必定是疼痛的一个主要组成部分。于是，当前疼痛研究的重点已转向理解构成神经元敏化和增强基础的兴奋性通路。尽管有大量证据支持存在疼痛的下行抑制机制，但关于脑干促通通路的报道却很稀少。在本文中，我们综述了连接脊髓与参与情绪和情感的脑干区域的5-羟色胺（5-HT）促通通路的相关证据。由于疼痛包含情感方面，我们认为这些5-HT通路和其他神经回路在决定疼痛程度、药物治疗效果方面很重要，并提供了一种情绪可改变痛觉的机制。
