Involvement of transient receptor potential vanilloid-1 in calcium current inhibition by capsaicin.
Capsaicin has been used as a topical analgesic to treat diverse pain conditions. We investigated the molecular mechanisms that mediate the inhibition of high-voltage-activated calcium channel currents (ICa) using trigeminal ganglion neurons and a heterologous expression system. Capsaicin inhibited ICa in capsaicin-sensitive trigeminal ganglion neurons, but not in capsaicin-insensitive neurons. Single-cell reverse-transcription polymerase chain reaction revealed the expression of TRPV1 only in capsaicin-sensitive neurons. Capsaicin inhibited ICa in transient receptor potential vanilloid-1-expressing C2D7 cells stably expressing human N-type calcium channels, whereas capsaicin failed to inhibit ICa in naïve C2D7 cells with no endogenous transient receptor potential vanilloid-1 expression. Calcium influx via transient receptor potential vanilloid-1 is not likely to play a critical role in capsaicin-induced ICa inhibition in trigeminal ganglion neurons. ICa inhibition might be one of the mechanisms for the analgesic effect of capsaicin.
Kim
Mi Sun
MS
Department of Physiology and Program in Molecular and Cellular Neuroscience, College of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
Park
Chul-Kyu
CK
Yeon
Kyu-Young
KY
Li
Hai Ying
HY
Jung
Sung Jun
SJ
Choi
Se-Young
SY
Lee
Sung Joong
SJ
Park
Kyungpyo
K
Kim
Joong Soo
JS
Oh
Seog Bae
SB
D000818:Animals; D015152:Blotting, Northern / Q000379:methods; D002118:Calcium / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology*; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014162:Transfection / Q000379:methods; D012668:Trigeminal Ganglion / Q000166:cytology
D002614:Chelating Agents; D012333:RNA, Messenger; D050916:TRPV Cation Channels; C494484:TRPV1 receptor; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002211:Capsaicin; D002118:Calcium