Vanilloid receptors, transient receptor potential vanilloid receptor 1 (TRPV 1), have been identified in afferent nerves and urothelial cells in the urinary bladder.Activation of these receptors induces bladder overactivity.In this study, we examined the effect of a novel TRPV1 antagonist (9515223-4, Neurogen Corporation) on the response of the bladder to the administration of capsaicin or menthol.