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

• Published in: International Urogynecology Journal Vol. 25; no. 12; pp. 1721 - 1727
• Main Authors: Izumi, Hideaki, Kaiho, Yasuhiro, Miyazato, Minoru, Kawamorita, Naoki, Nakagawa, Haruo, Arai, Yoichi
• Format: Journal Article
• Language: English
• Published: London Springer London 01.12.2014; Springer Nature B.V
• Subjects: Animals; Carbolines - pharmacology; Carbolines - therapeutic use; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Gynecology; Medicine; Medicine & Public Health; Muscle Relaxation - drug effects; Muscle Relaxation - physiology; Muscle, Smooth - drug effects; Muscle, Smooth - physiopathology; Original Article; Phosphodiesterase 5 Inhibitors - pharmacology; Phosphodiesterase 5 Inhibitors - therapeutic use; Rats; Rats, Sprague-Dawley; Reflex - drug effects; Reflex - physiology; Tadalafil; Treatment Outcome; Urethra - drug effects; Urethra - physiopathology; Urethral Diseases - drug therapy; Urethral Diseases - physiopathology; Urinary Incontinence, Stress - drug therapy; Urinary Incontinence, Stress - physiopathology; Urology; Sneeze; Smooth muscle; Stress urinary incontinence; Striated muscle
• ISSN: 0937-3462; 1433-3023
• DOI: 10.1007/s00192-014-2453-3

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 cmH 2 O, 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.