Belvisi M G, Miura M, Stretton D, Barnes P J
Department of Thoracic Medicine, National Heart and Lung Institute, Chelsea, London, UK.
Eur J Pharmacol. 1992 May 14;215(2-3):341-4. doi: 10.1016/0014-2999(92)90054-8.
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.
