title: Borneol inhibits TRPA1, a proinflammatory and noxious pain-sensing cation channel.
abstract: Borneol, a natural product isolated from several species of Artemisia, Blumea and Kaempferia, has a widespread use in traditional medicine. TRP ion channels are a class of nonselective cation channel proteins involved in a variety of physiological and pathological processes in mammals. TRPA1, a member of TRP family of cation channels, is involved in plethora of processes including noxious-cold, noxious-pain sensations, inflammation and the detection of irritant chemicals. Borneol is chemically related to camphor (a known inhibitor of TRPA1 ion channels); therefore, it is beneficial to investigate the effects of borneol on TRPA1. In the present investigation it was found that borneol inhibits TRPA1 mediated cationic currents in low millimolar range (IC50 0.3mM) in heterologous expression systems like Xenopus oocytes and in neurons cultured from trigeminal ganglia. Effects of nicotine, a known chemical irritant and agonist of TRPA1 are also inhibited by borneol in both systems. It is concluded that borneol, being an inhibitor of TRPA1, could be a safer therapeutic-combination in clinical situations where TRPA1 channelopathies like neuropathic-pain, trigeminal neuralgia or nicotine withdrawal treatments are involved.
authors.affiliation: Department of Pharmacy, Hazara University, Havelian Campus, Abbottabad, Pakistan.
authors.forename: Muhammad Azhar
authors.initials: MA
authors.lastname: Sherkheli
authors.affiliation: Department of Cell Physiology, Ruhr-University-Bochum, Bochum, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schreiner
authors.affiliation: Department of Pharmacy, Hazara University, Havelian Campus, Abbottabad, Pakistan.
authors.forename: Rizwanul
authors.initials: R
authors.lastname: Haq
authors.affiliation: Department of Cell Physiology, Ruhr-University-Bochum, Bochum, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Werner
authors.affiliation: Department of Cell Physiology, Ruhr-University-Bochum, Bochum, Germany.
authors.forename: Hanns
authors.initials: H
authors.lastname: Hatt
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology; D001892:Camphanes / Q000494:pharmacology*; D002478:Cells, Cultured; D051379:Mice; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000037:antagonists & inhibitors* / Q000502:physiology; D014276:Trigeminal Nerve / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D015220:Calcium Channels; D001892:Camphanes; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels; D009538:Nicotine; C022871:isoborneol; D002118:Calcium