Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers
<p>Abstract</p> <p>Background</p> <p>Previous studies have shown that the TRPV1 ion channel plays a critical role in the development of heat hyperalgesia after inflammation, as inflamed TRPV1-/- mice develop mechanical allodynia but fail to develop thermal hyperalgesia....
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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SAGE Publishing
2010-09-01
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| Series: | Molecular Pain |
| Online Access: | http://www.molecularpain.com/content/6/1/58 |
| _version_ | 1818498579417792512 |
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| author | Koerber H Richard McIlwrath Sabrina L Lawson Jeffrey J Malin Sacha A Anderson Collene E Jankowski Michael P Davis Brian M |
| author_facet | Koerber H Richard McIlwrath Sabrina L Lawson Jeffrey J Malin Sacha A Anderson Collene E Jankowski Michael P Davis Brian M |
| author_sort | Koerber H Richard |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Previous studies have shown that the TRPV1 ion channel plays a critical role in the development of heat hyperalgesia after inflammation, as inflamed TRPV1-/- mice develop mechanical allodynia but fail to develop thermal hyperalgesia. In order to further investigate the role of TRPV1, we have used an ex vivo skin/nerve/DRG preparation to examine the effects of CFA-induced-inflammation on the response properties of TRPV1-positive and TRPV1-negative cutaneous nociceptors.</p> <p>Results</p> <p>In wildtype mice we found that polymodal C-fibers (CPMs) lacking TRPV1 were sensitized to heat within a day after CFA injection. This sensitization included both a drop in average heat threshold and an increase in firing rate to a heat ramp applied to the skin. No changes were observed in the mechanical response properties of these cells. Conversely, TRPV1-positive mechanically insensitive, heat sensitive fibers (CHs) were not sensitized following inflammation. However, results suggested that some of these fibers may have gained mechanical sensitivity and that some previous silent fibers gained heat sensitivity. In mice lacking TRPV1, inflammation only decreased heat threshold of CPMs but did not sensitize their responses to the heat ramp. No CH-fibers could be identified in naïve nor inflamed TRPV1-/- mice.</p> <p>Conclusions</p> <p>Results obtained here suggest that increased heat sensitivity in TRPV1-negative CPM fibers alone following inflammation is insufficient for the induction of heat hyperalgesia. On the other hand, TRPV1-positive CH fibers appear to play an essential role in this process that may include both afferent and efferent functions.</p> |
| first_indexed | 2024-12-10T20:17:32Z |
| format | Article |
| id | doaj.art-6272ea0ff5d344fdada661f247dab51d |
| institution | Directory Open Access Journal |
| issn | 1744-8069 |
| language | English |
| last_indexed | 2024-12-10T20:17:32Z |
| publishDate | 2010-09-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | Molecular Pain |
| spelling | doaj.art-6272ea0ff5d344fdada661f247dab51d2022-12-22T01:35:09ZengSAGE PublishingMolecular Pain1744-80692010-09-01615810.1186/1744-8069-6-58Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibersKoerber H RichardMcIlwrath Sabrina LLawson Jeffrey JMalin Sacha AAnderson Collene EJankowski Michael PDavis Brian M<p>Abstract</p> <p>Background</p> <p>Previous studies have shown that the TRPV1 ion channel plays a critical role in the development of heat hyperalgesia after inflammation, as inflamed TRPV1-/- mice develop mechanical allodynia but fail to develop thermal hyperalgesia. In order to further investigate the role of TRPV1, we have used an ex vivo skin/nerve/DRG preparation to examine the effects of CFA-induced-inflammation on the response properties of TRPV1-positive and TRPV1-negative cutaneous nociceptors.</p> <p>Results</p> <p>In wildtype mice we found that polymodal C-fibers (CPMs) lacking TRPV1 were sensitized to heat within a day after CFA injection. This sensitization included both a drop in average heat threshold and an increase in firing rate to a heat ramp applied to the skin. No changes were observed in the mechanical response properties of these cells. Conversely, TRPV1-positive mechanically insensitive, heat sensitive fibers (CHs) were not sensitized following inflammation. However, results suggested that some of these fibers may have gained mechanical sensitivity and that some previous silent fibers gained heat sensitivity. In mice lacking TRPV1, inflammation only decreased heat threshold of CPMs but did not sensitize their responses to the heat ramp. No CH-fibers could be identified in naïve nor inflamed TRPV1-/- mice.</p> <p>Conclusions</p> <p>Results obtained here suggest that increased heat sensitivity in TRPV1-negative CPM fibers alone following inflammation is insufficient for the induction of heat hyperalgesia. On the other hand, TRPV1-positive CH fibers appear to play an essential role in this process that may include both afferent and efferent functions.</p>http://www.molecularpain.com/content/6/1/58 |
| spellingShingle | Koerber H Richard McIlwrath Sabrina L Lawson Jeffrey J Malin Sacha A Anderson Collene E Jankowski Michael P Davis Brian M Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers Molecular Pain |
| title | Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers |
| title_full | Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers |
| title_fullStr | Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers |
| title_full_unstemmed | Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers |
| title_short | Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers |
| title_sort | cutaneous c polymodal fibers lacking trpv1 are sensitized to heat following inflammation but fail to drive heat hyperalgesia in the absence of tpv1 containing c heat fibers |
| url | http://www.molecularpain.com/content/6/1/58 |
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