title: Capsazepine as a selective antagonist of capsaicin-induced activation of C-fibres in guinea-pig bronchi.
abstract: We investigated the action of capsazepine, an antagonist of the actions of capsaicin on sensory neurones, on the contractile responses evoked by capsaicin or by electrical field stimulation (EFS) in guinea-pig bronchi. Capsazepine (10(-5) M) selectively inhibited responses to capsaicin, producing a significant change in EC50 values but not the Hill coefficient (nH), suggesting that capsazepine acts as a competitive antagonist (apparent pKB = 5.12) whereas ruthenium red is a non-competitive antagonist. Capsazepine and ruthenium red were without effect on EFS-induced responses.
authors.affiliation: Department of Thoracic Medicine, National Heart and Lung Institute, Chelsea, London, UK.
authors.forename: M G
authors.initials: MG
authors.lastname: Belvisi
authors.forename: M
authors.initials: M
authors.lastname: Miura
authors.forename: D
authors.initials: D
authors.lastname: Stretton
authors.forename: P J
authors.initials: PJ
authors.lastname: Barnes
mesh_terms: D000818:Animals; D001980:Bronchi / Q000187:drug effects / Q000294:innervation*; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects*; D012430:Ruthenium Red / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D012430:Ruthenium Red; D013779:Tetrodotoxin; C071423:capsazepine; D002211:Capsaicin