Suramin inhibits spinal cord microglia activation and long-term hyperalgesia induced by formalin injection.


Journal Article

UNLABELLED: Previous studies in our laboratory have shown that long-term (a period of weeks) increases in pain-related behavior were correlated with the activation of spinal microglia after subcutaneous injection of formalin into the dorsal surface of 1 hind paw. The present study examined whether intrathecal delivery of suramin (a P2 receptor antagonist) blocks microglia activation and long-term hyperalgesia induced by formalin injection. Suramin was administered by using an osmotic pump attached to an intrathecal catheter. Suramin delivery (1.25 microg/kg/h) began 1 day before the formalin injection and lasted for 4 days. Rats were observed by using a modified hot plate test before and at different times after formalin injection. The spinal cord was surveyed for changes in microglia labeling as shown by OX-42 staining at different times after formalin injection. Suramin decreased both the hyperalgesic sensitivity to the thermal stimuli and microglial activation induced by formalin injection as compared to the saline-treated group. This suggests that adenosine triphosphate is one potential mediator that activates spinal cord microglia and enhances pain-related behavior in the formalin model. PERSPECTIVE: This report suggests that blocking specific spinal P2 receptors might decrease the central enhancement of pain caused by peripheral injury and inflammation. One mechanism might be by blocking the activation of spinal microglia. Thus, P2 antagonists might have therapeutic usefulness in certain pain conditions.

Full Text

Duke Authors

Cited Authors

  • Wu, Y; Willcockson, HH; Maixner, W; Light, AR

Published Date

  • February 2004

Published In

Volume / Issue

  • 5 / 1

Start / End Page

  • 48 - 55

PubMed ID

  • 14975378

Pubmed Central ID

  • 14975378

International Standard Serial Number (ISSN)

  • 1526-5900

Digital Object Identifier (DOI)

  • 10.1016/j.jpain.2003.09.006


  • eng

Conference Location

  • United States