PURPOSE: We established the longitudinal changes in bladder contractility and compliance as a result of urethral obstruction using a guinea pig model. MATERIALS AND METHODS: Obstruction was induced in guinea pigs by a silver ring around the urethra. Urodynamic studies were performed longitudinally in individual animals. Bladder contractility and compliance were calculated from the measured bladder pressure and urine flow rate. RESULTS: Bladder contractility developed in distinct phases. It reached a maximum 200% increase after an average of 3.25 weeks concomitant with an almost 2-fold increase in urethral resistance, remained 150% to 200% increased during weeks 4 to 7 and then decreased to starting levels again, while urethral resistance remained almost 2-fold increased. Bladder compliance decreased by 80% during the first 3 weeks and continued to decrease to 5% of its original value after 10 to 11 weeks. CONCLUSIONS: Our data indicate that as a result of obstruction bladder function passes through a specific sequence of stages, including first a compensatory increase in contractility, then a stabilization phase and finally a decompensation state. In contrast bladder compliance shows a continuous decrease. The data suggest that for assessing how far a bladder has deteriorated due to obstruction a combination of functional and structural data may be warranted

*Muscle Contraction, Animals, Disease Models, Animal, Follow-Up Studies, Guinea Pigs, Male, Muscle, Smooth/*physiopathology, Urethral Obstruction/*physiopathology, Urinary Bladder/physiopathology, Urodynamics
dx.doi.org/10.1016/S0022-5347(05)67241-2, hdl.handle.net/1765/14249
The Journal of Urology
Erasmus MC: University Medical Center Rotterdam

Kok, D.J, Wolffenbuttel, K.P, Minekus, J, van Mastrigt, R, & Nijman, R.J.M. (2000). Changes in bladder contractility and compliance due to urethral obstruction: a longitudinal followup of guinea pigs. The Journal of Urology, 1021–1024. doi:10.1016/S0022-5347(05)67241-2