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 μM) or by the TRPV1 antagonist capsazepine (30 μM). These results suggest that stimulation of capsaicin-sensitive sensory fibers contributes, at least in part, to PAR-2-mediated bladder contractions in rats.