Role of capsaicin-sensitive sensory nerves in protease-activated receptor-2-mediated contraction of rat urinary bladder

The capsaicin receptor, transient receptor potential vanilloid receptor 1 (TRPV1), colocalizes with protease-activated receptors (PARs) in the urinary bladder, but functional interaction between TRPV1 and PARs remains to be clarified. In the present study, the role of capsaicin-sensitive sensory neurons in contraction induced by activation of PAR-2 was investigated in the rat urinary bladders. The contractile responses to trypsin and the PAR-2 agonist 2-furoyl-LIGRL-NH2 were significantly attenuated by either desensitization of sensory neurons achieved by capsaicin (10 mu M) or by the TRPV1 antagonist capsazepine (30 mu M). These results suggest that stimulation of capsaicin-sensitive sensory fibers contributes, at least in part, to PAR-2-mediated bladder contractions in rats. (c) 2007 Elsevier B.V. All rights reserved.