TY - JOUR T1 - Bitter taste receptors are expressed and induce relaxation of human bronchi JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P1584 AU - Stanislas Grassin-Delyle AU - Charlotte Abrial AU - Sarah Taleb-Fayad AU - Marion Brollo AU - Emmanuel Naline AU - Philippe Devillier Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P1584.abstract N2 - Introduction: Bitter-taste receptors (TAS2Rs) have recently been involved in the relaxation of mouse and guinea pig airways, and increased expression of TAS2Rs was shown in blood leucocytes from asthmatic children. We addressed the expression and relaxant effect of TAS2Rs in human bronchi.Methods: Human bronchi were isolated from resected lungs and TAS2R transcripts were assessed with RT-qPCR. Relaxation to TAS2R agonists was tested in organ bath in the presence or absence of pharmacological modulators of the signalling pathways involved in bronchial relaxation.Results: The non-selective agonists chloroquine, quinine, caffeine, strychnine and diphenidol produced a concentration-dependant relaxation, with a maximal effect equivalent to about 90% of the relaxation observed with 3 mM theophylline. pD2 values were between 3.7 and 4.6, similar to that of theophylline but 3- to 5-fold less than that with formoterol and isoproterenol. Denatonium, saccharin and colchicine did not produce relaxation. Receptor expression analysis together with the use of most selective agonists suggested a predominant role for TAS2R5, 10 and 14 in the bitter taste agonist-induced relaxation. In contrast to the non-selective agonist chloroquine, the relaxation to the selective TAS2R5 agonist chloroquine was in part dependent from an intact epithelium. Bitter taste agonist-induced relaxation was independent from the intracellular signalling pathways modulated by conventional bronchodilators.Conclusion: The stimulation of TAS2Rs expressed in human bronchi induces a marked relaxation. Bitter taste receptors may become a target for the pharmacological management of obstructive lung diseases. ER -