Effects of phosphodiesterase type 5 inhibitor, tadalafil, on continence reflex in rats.

ABSTRACT

INTRODUCTION AND HYPOTHESIS: Effects of tadalafil, a phosphodiesterase type 5 inhibitor, on the urethral continence reflex induced by sneezing were investigated. METHODS: The amplitude of urethral pressure responses during sneezing (A-URS) and urethral baseline pressure (UBP) were measured in female rats using a microtransducer-tipped catheter. Sneeze leak-point pressure (S-LPP), defined as the lowest amount of pressure required to induce fluid leakage from the urethral orifice during sneezing, was measured in rats with stress urinary incontinence (SUI) induced by vaginal distension. Values were determined before and after tadalafil administration. RESULTS: Tadalafil dose dependently and significantly decreased A-URS and S-LPP. At the highest dose tested (6.0 mg/kg), A-URS and S-LPP decreased from 49.7 to 32.3 and from 63.9 to 44.2 cmH2O, respectively, whereas UBP did not significantly change. CONCLUSIONS: Tadalafil attenuated the sneeze-induced urethral continence reflex by relaxing the striated muscles of the external urethral sphincter.