Role of vanilloid receptors in thermal hyperalgesia induced by intraplantar endothelin-1 administration / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To assess the role of vanilloid receptor (VR) in thermal hyperalgesia induced by intraplantar endothelin-1 (ET-1) injection.</p><p><b>METHODS</b>VR gene-knockout mice (KO group) and wild type C57BL/6J mice (WT group) in 3 subgroups were subjected to intraplantar administration of ET-1 at the doses of 3, 10, 30 and 100 pmol (dissolved in 10 microl of PBS, pH 7.4, n=6 in each group), respectively. The latency time of paw withdrawal (PWT) from heat irradiation stimulation was recorded before injection and 15, 30, 45 and 60 min after injection.</p><p><b>RESULTS</b>ET-1 induced thermal hyperalgesia in both groups. The mice in WT group showed a more sharply shortened PWT than those in KO group. ET-1 decreased PWT as the dose administered increased in WT group, which was different from the responses of the KO mice. At the dose of 100 pmol of ET-1, no further decrement of latency time was observed in WT group, whereas such response occurred at 30 pmol in KO group.</p><p><b>CONCLUSION</b>Intraplantar injection of ET-1 induces thermal hyperalgesia mediated partially by VR.</p>