Transient receptor potential melastatin (TRPM8), activated by menthol and cool temperatures (8οC to 28οC) has been identified in a number of human genitourinary tract tissues, including urinary bladder (1). The role of these channels in the physiology and pathophysiology of the bladder is unclear and only a few studies have investigated their functional role in mediating the detrusor contraction (2). The aim of this study was to investigate the effect of menthol, a TRPM8 channel agonist, on detrusor contractions in pig urinary bladder. Fresh female pig bladders were obtained from the local abattoir and longitudinal strips of detrusor (denuded) mounted under isometric conditions in 0.2ml microbaths at 36οC. After equilibration, strips were exposed to 10μM carbachol at 20-min intervals, and washed between treatments. Once contractions induced by carbachol had stabilized, 0.1, 0.3 or 1mM menthol or vehicle controls (0.05%, 0.1% and 0.5% ethanol) were applied to the strips 11 min before application of carbachol. The results are expressed as percentage of inhibition of the contractile force before the addition of menthol or vehicle. All data are expressed as the mean±SEM. Statistical analysis was carried out by using repeated measure ANOVA followed by Dunett’s post hoc test. Contractile responses to carbachol of pig bladder detrusor strips (n=18) were significantly (p<0.01) inhibited by 0.3mM (76.19±5.32%) and 1mM (98.80±0.78) menthol. Ethanol which was used as a vehicle in these experiments had no effect on detrusor contractions at all concentrations. These results indicate that TRPM8 channels may play an important role in modulation of smooth muscle contractility. At present the exact mechanisms underlying the detrusor responses to TRPM8 channel modulation remain unclear and need to be further clarified.