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

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.