尽管疼痛和抑郁共病的情况在临床上很常见，但是抑郁和疼痛之间的关系尚不清楚。近日，中科院心理研究所心理健康院重点实验室罗非研究员、王锦琰副研究员及其团队利用大鼠抑郁模型探索了抑郁情绪对痛行为的影响。

实验采用经典的不确定预期的温和应激模型（unpredictable chronic mild stress, UCMS）诱导大鼠出现抑郁情绪，采用糖水偏好测试、旷场测试以及高架十字迷宫测试评价动物的情绪行为，并通过自发痛（足底注射福尔马林）和诱发痛（足底施加辐射热刺激）模型观察痛行为的改变。结果显示，与非抑郁组大鼠相比，抑郁大鼠的福尔马林自发痛行为显著增强，与临床观察到的现象一致。然而有趣的是，抑郁大鼠对于辐射热刺激所诱发的痛反应却较正常大鼠显著减弱。这些结果表明，抑郁情绪对于诱发痛和自发痛的影响是不同的。慢性给予抗抑郁药物氟西汀能够翻转大鼠的抑郁行为，同时大鼠的痛行为也都相应恢复到了正常水平，表明痛行为的改变与抑郁的发生有关。此外，本研究还观察了慢性炎症痛大鼠的抑郁相关行为，并发现有抑郁样行为改变的趋势。总之，该研究提出，抑郁情绪对个体的痛感知的影响是多样的，表现为对自发痛的加重和对诱发痛的抑制，从而解释了临床抑郁患者其疼痛敏感性变化的不一致性。该研究有助于进一步研究疼痛和抑郁之间的复杂关系，为推动临床治疗提供科学的理论依据。

原始出处：

Journal of Pain 22 January 2010 doi:10.1016/j.jpain.2009.07.002

Depression Shows Divergent Effects on Evoked and Spontaneous Pain Behaviors in Rats

Miao Shi, Jin-Yan Wang, Fei Luo

Although it has been accepted that depression and pain are common comorbidities, their interaction is not fully understood. The present study was aimed to investigate the effects of depression on both evoked pain behavior (thermal-induced nociception and hyperalgesia) and spontaneous pain behavior (formalin pain) in rats. An unpredictable chronic mild stress (UCMS) paradigm was employed to develop a classical depression. The emotional behaviors were assessed by sucrose preference test, open field test, and elevated plus-maze test. The results showed that the depressed rats always exhibited stronger tolerance to noxious thermal stimulation under both normal and complete Freund's adjuvant (CFA)-induced chronic pain conditions, when compared to nondepressed animals. Interestingly, the spontaneous nociceptive behaviors induced by formalin injection were significantly enhanced in rats exposed to UCMS in comparison to those without UCMS. Systemic administration of antidepressant fluoxetine significantly restored the nociceptive behaviors to normal level in depressed animals. An additional finding was that the inflammatory rats tended to display depressive-like behaviors without being exposed to UCMS. These results demonstrated that depression can have different effects on stimulus-evoked pain and spontaneous pain, with alleviation in the former while aggravation in the latter.

Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Science, Beijing, China
Neuroscience Research Institute and Department of Neurobiology, Peking University, Beijing, China