title: Involvement of transient receptor potential vanilloid-1 in calcium current inhibition by capsaicin.
abstract: 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.
authors.affiliation: Department of Physiology and Program in Molecular and Cellular Neuroscience, College of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
authors.forename: Mi Sun
authors.initials: MS
authors.lastname: Kim
authors.forename: Chul-Kyu
authors.initials: CK
authors.lastname: Park
authors.forename: Kyu-Young
authors.initials: KY
authors.lastname: Yeon
authors.forename: Hai Ying
authors.initials: HY
authors.lastname: Li
authors.forename: Sung Jun
authors.initials: SJ
authors.lastname: Jung
authors.forename: Se-Young
authors.initials: SY
authors.lastname: Choi
authors.forename: Sung Joong
authors.initials: SJ
authors.lastname: Lee
authors.forename: Kyungpyo
authors.initials: K
authors.lastname: Park
authors.forename: Joong Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Seog Bae
authors.initials: SB
authors.lastname: Oh
mesh_terms: 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
chemical_list: 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