Functional expression of thermo-transient receptor potential channels in dental primary afferent neurons: implication for tooth pain.
Temperature signaling can be initiated by members of transient receptor potential family (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. This study investigated the expression of thermo-TRP channels in dental primary afferent neurons of the rat identified by retrograde labeling with a fluorescent dye in maxillary molars. Single cell reverse transcription-PCR and immunohistochemistry revealed expression of TRPV1, TRPM8, and TRPA1 in subsets of such neurons. Capsaicin (a TRPV1 agonist), menthol (a TRPM8 agonist), and icilin (a TRPM8 and TRPA1 agonist) increased intracellular calcium and evoked cationic currents in subsets of neurons, as did the appropriate temperature changes (>43 degrees , <25 degrees , and <17 degrees C, respectively). Some neurons expressed more than one TRP channel and responded to two or three corresponding stimuli (ligands or thermal stimuli). Immunohistochemistry and single cell reverse transcription-PCR following whole cell recordings provided direct evidence for the association between the responsiveness to thermo-TRP ligands and expression of thermo-TRP channels. The results suggest that activation of thermo-TRP channels expressed by dental afferent neurons contributes to tooth pain evoked by temperature stimuli. Accordingly, blockade of thermo-TRP channels will provide a novel therapeutic intervention for the treatment of tooth pain.
Park
Chul-Kyu
CK
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Kim
Mi Sun
MS
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Fang
Zhi
Z
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Li
Hai Ying
HY
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Jung
Sung Jun
SJ
Department of Physiology, College of Medicine, Kangwon National University, Chunchon 200-710, Korea.
Choi
Se-Young
SY
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Lee
Sung Joong
SJ
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Park
Kyungpyo
K
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Kim
Joong Soo
JS
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749.
Oh
Seog Bae
SB
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749. Electronic address: odolbae@snu.ac.kr.
D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009475:Neurons, Afferent / Q000378:metabolism*; D010146:Pain; D051381:Rats; D017207:Rats, Sprague-Dawley; D000074025:TRPA1 Cation Channel; D050053:TRPM Cation Channels / Q000096:biosynthesis*; D050916:TRPV Cation Channels / Q000096:biosynthesis*; D013696:Temperature; D014098:Toothache / Q000378:metabolism*; D050051:Transient Receptor Potential Channels / Q000096:biosynthesis* / Q000378:metabolism*
D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050053:TRPM Cation Channels; C425966:TRPM8 protein, human; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D050051:Transient Receptor Potential Channels; D002118:Calcium