[Role of vanilloid receptors in thermal hyperalgesia induced by intraplantar endothelin-1 administration].
OBJECTIVE
To assess the role of vanilloid receptor (VR) in thermal hyperalgesia induced by intraplantar endothelin-1 (ET-1) injection.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Intraplantar injection of ET-1 induces thermal hyperalgesia mediated partially by VR.
Ji
Wen-Jin
WJ
Department of Anesthesiology, Guangdong Provincial People's Hospital, Guangzhou 510080, China. wenjj@msn.com
Liang
Jie-Xian
JX
Zhao
Guo-Dong
GD
D000818:Animals; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000008:administration & dosage / Q000633:toxicity; D005838:Genotype; D006358:Hot Temperature; D006930:Hyperalgesia / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010147:Pain Measurement / Q000379:methods; D050916:TRPV Cation Channels / Q000235:genetics / Q000502:physiology*
D019332:Endothelin-1; D050916:TRPV Cation Channels