Cystometrical Evaluation of Bladder Instability in Rats with Infravesical Outflow Obstruction

Abstract

Cystometries were performed in normal rats and in rats with bladder hypertrophy due to infravesical outflow obstruction. Investigations were performed in the presence and absence of anesthesia. pentobarbital anesthesia depressed spontaneous contractile activity in the bladder and the micturition reflex, thereby making measurements of other variables, such as bladder capacity and residual volume, impossible. In conscious animals infravesical outflow obstruction led to development of increased bladder capacity, marked residual volume, and unstable detrusor contractions. The model seems to be well suited for further evaluation of the mechanisms involved in the development of detrusor instability and the responses to pharmacological treatment.

Improved model for the establishment and evaluation of detrusor overactivity in female Wistar rats

“…The impairment of bladder and its innervation and peri--urethral blood vessel was avoided. Therefore, compared to the previous studies (3,7), the influence of injury on bladder, which might be the etiology of DO, was excluded. 3.…”

“…The most common method to create a model of DO rats involved reduction of the urethral diameter by placing a suture around the urethra (7), and significant increases were demonstrated in voiding frequency, voiding pressure and bladder capacity. Moreover, DO rats showed a pronounced "non-voiding contractions" during cystometry, and the categorization of different types of DO in conscious rats has been described (3).…”

“…However, many disadvantages presented in the model of DO rats established in the previous studies. For example, DO rats were established by partial obstruction with a method of transabdominal pathway, and the abdomen was opened through a midline incision (7). The architecture of cavitas pelvis was dissected, and the trauma might induce impairment of nerves and deformity of bladder which might influence the function of bladder.…”

Effects of morphine metabolites on micturition in normal, unanaesthetized rats

“…administration of drugs as described in detail previously (Igawa et al, 1993b). Thereafter, the abdomen was opened through a midline incision, and a polyethylene catheter (Clay-Adams PE-50, NJ, U.S.A.) was implanted into the bladder through the dome as described previously (Malmgren et al, 1987). The catheters were tunnelled subcutaneously and orifices were made on the back of the animal.…”

“…After each drug administration, recording was continued for at least another 120 min. The following cystometric parameters were investigated (Malmgren et al, 1987): basal pressure (the lowest bladder pressure during filling), threshold pressure (bladder pressure immediately prior to micturition), micturition pressure (the maximum bladder pressure during micturition), bladder capacity (residual volume at the latest previous micturition plus volume of infused saline at the micturition), micturition volume (volume of expelled urine), residual volume (bladder capacity minus micturition volume), and spontaneous contractile activity (mean amplitude and frequency of bladder pressure fluctuations during 2 min prior to micturition). Analysis was performed for a 20 min period before drug administration.…”