A contribution of neurokinin-1 receptor to formalin-induced c-fos expression in the rat spinal dorsal horn

Yuan Xiang Tao, Feng Wei, Zhi Qi Zhao

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Formalin applied to a hindpaw of the rat resulted in c-fos expression in the spinal dorsal horn neurons on the ipsilateral side of stimulation. The role of neurokinin-1 (NK-1) receptor in this response was examined using a selective NK-1 antagonist L-668169. L668169 administered intrathecally (1 μg/10 μl, 10 μg/10 μl) 15 min before injection of 2% formalin into one hindpaw significantly decreased the number of Fos-labeled neurons in the dorsal horn. A smaller dose of L-668169 (0.1 μg/10 μl)was ineffective. It was also shown that a selective NK-1 agonist Sar-SP perfused intrathecally (10 μg/10 μl) did result in the production of c-fos mainly in laminae I and that SP-like immunoreactive varicosities apposed neurons with Fos-labeled nuclei at their perikaryal membrane in the superficial laminae. These results indicate that NK-1 receptors may contribute to the activation of c-fos in the spinal dorsal horn neurons.

Original languageEnglish (US)
Pages (from-to)105-108
Number of pages4
JournalNeuroscience Letters
Issue number2-3
StatePublished - Jan 17 1997



  • C-fos
  • dorsal horn
  • neurokinin-1 receptor
  • nociception
  • rat
  • spinal cord
  • substance P

ASJC Scopus subject areas

  • Neuroscience(all)

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