Effects of intracisternal injection of interleukin-6 on nociceptive jaw opening reflex and orofacial formalin test in freely moving rats

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• 作者：Choi ; Hyo-Soon ; Ju ; Jin-Sook ; Lee ; Ho-Jeong ; Kim ; Byung-Chul ; Park ; Jae-Sik ; Ahn ; Dong-Kuk
• 关键词：Formalin test ; Freely moving rats ; Hyperalgesia ; IL-6 ; Intracisternal ; JOR
• 刊名：Brain Research Bulletin
• 出版年：2003
• 出版时间：January 30, 2003
• 年：2003
• 卷：59
• 期：5
• 页码：365-370
• 全文大小：215 K

文摘

The present study was performed to investigate the effects of central cytokines on the modulation of nociception in the orofacial area. To achieve this purpose, a nociceptive jaw opening reflex and an orofacial formalin test were monitored before and after intracisternal administration of interleukin-6 (IL-6) in freely moving rats. In the nociceptive jaw opening reflex, the digastric electromyogram (dEMG) was not significantly changed after intracisternal injection of 200pg and 2ng IL-6. However, 20ng IL-6 suppressed dEMG to 74±7 % of the control values. In the inflammatory orofacial formalin test, intracisternal injection of 200pg and 2ng IL-6 did not change the number of noxious behavioral responses produced by formalin injection. However, 20ng IL-6 injected intracisternally significantly increased the number of noxious behavioral responses produced by formalin. The hyperalgesic action of intracisternal IL-6 in the orofacial formalin test was blocked by pretreatment with interleukin-1 (IL-1) receptor antagonist. These results suggest that IL-6 injected intracisternally modulates the transmission of nociceptive information in the orofacial area. However, the hypo/hyper-algesic response of central cytokines seems to depend on the orofacial pain model. The hyperalgesic response of central IL-6 seems to be mediated by the IL-1 receptor.