Warm temperature-sensitive transient receptor potential vanilloid 4 (TRPV4) plays an essential role in thermal hyperalgesia.
Animals sense various ranges of temperatures by cutaneous thermal stimuli. Transient receptor potential vanilloid 4 (TRPV4) is a cation channel activated at a warm temperature (over 30 degrees C) in exogenously expressed cells. We found in the present study that TRPV4 is essential in thermal hyperalgesia at a warm temperature in vivo. TRPV4-/- and TRPV4+/+ mice exhibited the same latency of escape from 35-50 degrees C hotplates. Neuronal activity in the femoral nerve, however, revealed that the number and activity level of neurons decreased in response to a warm temperature in TRPV4-/- mice. TRPV4-/- mice displayed a significantly longer latency to escape from the plates at 35- 45 degrees C when hyperalgesia was induced by carrageenan without changes in foot volumes. TRPV4 therefore determines the sensitivity rather than the threshold of painful heat detection and plays an essential role in thermal hyperalgesia.
Todaka
Hiroshi
H
Department of Pharmacology, Division of Molecular Pharmacology, Jichi Medical School 3311-1, Yakushiji, Minamikawachi, Tochigi 329-0498, Japan.
Taniguchi
Junichi
J
Satoh
Jun-ichi
J
Mizuno
Atsuko
A
Suzuki
Makoto
M
D000818:Animals; D002351:Carrageenan / Q000633:toxicity; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D006930:Hyperalgesia / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D017933:Peripheral Nervous System / Q000187:drug effects / Q000378:metabolism; D050916:TRPV Cation Channels
D027682:Cation Transport Proteins; D007473:Ion Channels; D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; D002351:Carrageenan