Objective     To explore the effects of intravesical adenosine triphosphate (ATP) and pyridoxalphosphate-6-azophenyl-2’4’-disulfonic (PPADS) on the function of normal and detrusor instable bladders of rats.      Methods     The model of bladder outlet obstruction (BOO) was inflicted in 30 female Sprague-Dawleys (SD) rats. Another normal 15 female SD rats served as control. After 6 weeks

a catheter was implanted into the rat bladder. Three days later

a cystometry was performed in conscious state. The rats were divided into stable and unstable groups. After a bolus infusion of ATP or PPADS into bladder

a same cystometry was performed in the conscious unstable BOO rats and the stabl

e normal rats again. Cytometric parameters were evaluated before and after drug administration.      Results     There was 72% detrusor instability (DI) in BOO rats. The ATP decreased the functional bladder capacity

shortened the interval-voiding time in both DI group and normal rats without DI. 70% normal rats without DI were induced detrusor instable contractions. PPADS increased the functional bladder capacity

prolonged the interval-voiding time in both groups. Specially

the frequency of instable contractions in DI rats was obviously decreased (

P

<

0.05).      Conclusion     Purinoceptors play important roles in bladder micturition reflex and detrusor instable contractions.