Increased TRPA1, TRPM8, and TRPV2 expression in dorsal root ganglia by nerve injury.
Thermosensitive TRP channels display unique thermal responses, suggesting distinct roles mediating sensory transmission of temperature. However, whether relative expression of these channels in dorsal root ganglia (DRG) is altered in nerve injury is unknown. We developed a multiplex ribonuclease protection assay (RPA) to quantify rat TRPV1, TRPV2, TRPV3, TRPV4, TRPA1, and TRPM8 RNA levels in DRG. We used the multiplex RPA to measure thermosensitive TRP channel RNA levels in DRG from RTX-treated rats (300 microg/kg) or rats with unilateral sciatic nerve chronic constriction injury (CCI). TRPV1 and TRPA1 RNA were significantly decreased in DRG from RTX-treated rats, indicating functional colocalization of TRPA1 and TRPV1 in sensory nociceptors. In DRG from CCI rats, TRPA1, TRPV2, and TRPM8 RNA showed slight but significant increases ipsilateral to peripheral nerve injury. Our findings support the hypothesis that increased TRP channel expression in sensory neurons may contribute to mechanical and cold hypersensitivity.
Frederick
J
J
Western Connecticut State University, 181 White Street, Danbury, CT 06810, USA. frederickj@wcsu.com
Buck
M E
ME
Matson
D J
DJ
Cortright
D N
DN
D000818:Animals; D017487:Ankyrins; D015220:Calcium Channels / Q000378:metabolism*; D003080:Cold Temperature / Q000009:adverse effects; D005727:Ganglia, Spinal / Q000293:injuries / Q000378:metabolism*; D006358:Hot Temperature / Q000009:adverse effects; D006930:Hyperalgesia / Q000209:etiology / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries / Q000378:metabolism; D020426:Sciatic Neuropathy / Q000378:metabolism*; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050053:TRPM Cation Channels / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000378:metabolism*; D015854:Up-Regulation
D017487:Ankyrins; D015220:Calcium Channels; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050053:TRPM Cation Channels; D050916:TRPV Cation Channels; C480976:Trpa1 protein, rat; C498947:Trpm8 protein, rat; C476722:Trpv2 protein, rat