Restoration of rat bladder function following release of short- and long-term partial outflow obstruction.

Detrusor dysfunction does not recover in some patients with benign prostatic hyperplasia (BPH) even after prostate resection. 'We studied the functional restoration of the rat bladder after release of short- or long-term outflow obstruction. Bladder function was assessed by in vivo infusion cystometry and an in vitro organ bath technique. There were no significant differences in bladder weight and contractile strength induced by stimuli in detrusor muscle strips from obstructed rats and age-matched control rats. After short-term obstruction the whole bladder pressure generated in vitro by field stimulation, bethanechol, ATP, and KCl completely recovered to control levels. In contrast, after long-term obstruction, the whole bladder pressure in response to field stimulation remained significantly lower than in controls. Infusion cystometry variables, including the pressure at which micturition was induced, maximal voiding pressure, capacity, and residual urine volume, were similar between controls and rats subjected to short-term obstruction. However, the maximal voiding pressure after long-term obstruction was significantly less than that of controls.