Effects of intrathecal isoflurane administration on nociception and Fos expression in the rat spinal cord

Chun Ran Liu, Qiao Zhi Duan, Wei Wang, Yan Yan Wei, Hui Zhang, Yun Qing Li, Sheng Xi Wu, Li Xian Xu

Research output: Contribution to journalArticle


Background and objective Isoflurane has been used as an inhaled anaesthetic for nearly 30 years. Isoflurane inhalation during anaesthesia also produces an anti-nociceptive effect. Whether this occurs at the spinal or supraspinal level remains unknown. With a novel type of liquid isoflurane, the present study examined the effects of intrathecal isoflurane on the nociceptive response and Fos expression in the rat spinal cord. Methods Thirty-six rats were randomly assigned to three groups as follows: group A (n=6), intrathecal physiological saline 50μl kg -1; and group B and C (n=6 each), intrathecal isoflurane at doses of 25ml kg -1 or 50μl kg -1, respectively. Noxious thermal (Hargreaves test), mechanical (von Frey test) and chemical (formalin 5%, 50μl) stimuli were applied to a hind paw after intrathecal isoflurane injection to study its antinociceptive effect. In addition, the expression of Fos protein and c-fos mRNA in the spinal dorsal horns was detected by immunohistochemistry and real-time reverse transcriptase PCR, respectively. Results Compared with the physiological saline control, intrathecal isoflurane significantly suppressed spontaneous paw flinches in rats induced by formalin injection and paw withdrawal induced by thermal and mechanical stimuli in a dose-dependent manner. Immunohistochemistry and real-time reverse transcriptase PCR revealed that isoflurane administration inhibited formalin injection-induced c-fos expression in the spinal cord. Conclusions These data suggest that isoflurane can exert antinociceptive effects at the spinal level by preventing neuronal activation. Eur J Anaesthesiol 2011;28:112-119 Published online 24 November 2010

Original languageEnglish (US)
Pages (from-to)112-119
Number of pages8
JournalEuropean Journal of Anaesthesiology
Issue number2
StatePublished - Feb 1 2011
Externally publishedYes


  • Analgesics
  • Intrathecal isoflurane
  • Liquid isoflurane
  • Rat

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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