Expression of the spinal 5-HT7 receptor and p-ERK pathway in the carrageenan inflammatory pain of rats|RISS 상세보기

다국어 초록 (Multilingual Abstract)

Background: Although the inhibitory role of the 5-hydroxytrypatmine receptor 7(5-HT7R) on nociceptive processingis generally recognized, an excitatory effect associated with a reduced 5-HT7R expression has also been observed in thenerve injury model. In the carrageenan model, no significant effect is produced by the 5-HT7R activation, but the changein 5-HT7R expression has not been examined. Lesioning of the spinal serotonergic pathway enhances allodynia in thecarrageenan model, but it also relieves several other pain states, including in the formalin model. While lesioning suppressesthe activation of the extracellular signal-regulated kinase (ERK) of the spinal cord in the formalin model, its rolein the carrageenan model has not been reported.
Methods: Following intraplantar injections of carrageenan, the spinal 5-HT7R expression was examined using Westernblotting in male Sprague-Dawley rats. The effect of serotonergic pathway lesioning with intrathecal 5,7-dihydroxytryptamine(5,7-DHT) on the expression of the phospho-ERK was measured.
Results: The expression of the 5-HT7R in the carrageenan model was not significantly different from that of naive animals.
The expression of the spinal p-ERK in the carrageenan model was significantly increased, but returned to the levelof a naive rat 1 hour after the carrageenan injection. However, it remained significantly higher 1 hour after the injectionin the animals treated with 5,7-DHT than in the naive and control rats.
Conclusions: The expression of the spinal 5-HT7R is not altered by peripheral inflammation with carrageenan, suggestingthat the lack of antinociceptive effect of the 5-HT7R activation is partly attributable to the absence of changes in theexpression of the 5-HT7R in the spinal cord. The extended increase of the spinal p-ERK might be related to the enhancedpain behavior in the animals with lesions of the spinal serotonergic pathway in the carrageenan model.

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참고문헌 (Reference)

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