Formalin-induced nociception activates a monoaminergic descending inhibitory system
Formalin-induced nociception activates a monoaminergic descending inhibitory system
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DOI：
10.1016/s0006-8993(98)01086-5
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发表时间：
1998-12-14
期刊：
影响因子：
2.9
通讯作者：
Namiki, A
中科院分区：
文献类型：
--
作者：
Omote, K;Kawamata, T;Namiki, A
长时间或重复伤害性刺激引起的传入痛通路的神经可塑性可能有助于激活中枢神经系统的内在抑制机制。为了阐明单胺能下行抑制系统在急性伤害性感受和炎性疼痛中的作用，我们研究了该抑制系统是否会调节福尔马林诱导的伤害性感受的紧张性反应。在大鼠后爪足底皮下注射2%福尔马林之前或之后，鞘内注射α 2肾上腺素能拮抗剂育亨宾或5-羟色胺拮抗剂麦角新碱。在另一系列的实验中，对未处理的大鼠和福尔马林处理后的大鼠的脊髓背侧一半的组织进行取样，并通过HPLC进行单胺水平的分析。皮下福尔马林诱发注射足的双相退缩行为。鞘内预处理育亨宾和麦角新碱产生了显着增加退缩的数量比对照组在第1阶段，中期和第2阶段。育亨宾和甲基麦角酰胺治疗后，在第2阶段退缩的数量显着增加。此外，福尔马林注射诱导显着增加去甲肾上腺素，MHPG，血清素（5-羟色胺; 5-HT）和5-HIAA浓度在同侧和对侧背侧的一半。这些结果表明，由福尔马林诱导的化学和/或炎性伤害性感受产生的疼痛状态是在单胺能（去甲肾上腺素能和肾上腺素能）下行抑制系统的调制下。(C)1998 Elsevier Science B. V.保留所有权利。
Neural plasticity of afferent pain pathways that is induced by prolonged or repeated noxious stimuli may contribute to activate intrinsic inhibitory mechanisms in CNS. In order to clarify the role of the monoaminergic descending inhibitory system in acute nociception and inflammatory pain, we examined if this inhibitory system would modulate the tonic response to formalin-induced nociception. Yohimbine, alpha 2 adrenergic antagonist, or methysergide, serotonin antagonist was administered intrathecally before or after subcutaneous 2% formalin injection into the plantar of the hind paw in rats. In another series of the experiment, the tissue of the spinal dorsal half of the untreated rats and post-formalin-treated rats were sampled and analyses of monoamine levels were carried out by HPLC. The subcutaneous formalin evoked biphasic flinching behavior of the injected paw. Intrathecal pretreatment with yohimbine and methysergide produced a significantly greater increase in the number of flinches than in the control in phase 1, intermediate period and phase 2. Posttreatment with yohimbine and methysergide showed a significantly greater increase in the number of flinches in phase 2. Furthermore, formalin injection induced significant increases in noradrenaline, MHPG, serotonin (5-hydroxytryptamine; 5-HT) and 5-HIAA concentrations in both the ipsi- and contralateral dorsal halves. These results suggest that the pain state produced by formalin-induced chemical and/or inflammatory nociception is under the modulation of the monoaminergic (noradrenergic and serotonergic) descending inhibitory system. (C) 1998 Elsevier Science B.V. All rights reserved.