Time-course of the effect of i.v. administration of oxybutynin and tolterodine on BVC and MP in conscious rats with bladder infused with diluted acetic acid. Data represent the mean (± S.E.) of BVC (ml) and MP (mmHg) values recorded before acetic acid infusion (-60 min), at the end of the first hr of acid infusion (0 min) and at different times after administration of: upper panel – vehicle (0.1 ml/kg; circles; n = 8) or oxybutynin (1 mg/kg; squares; n = 8); lower panel – vehicle (0.1 ml/kg; circles; n = 7) or tolterodine (0.3 mg/kg; squares n = 8). Rats were utilized 1 day after catheter implantation and during continuous infusion of acid. Statistical analysis indicates significativity vs vehicle-treated group at considered times.