Abstract
The effects of HY-770 on micturition reflexes in rats, dogs and cats and urethral pressure in dogs were compared with those of flavoxate·HCl (flavoxate), terodiline·HCl (terodiline) and oxybutynin·HCl (oxybutynin). 1) HY-770, in intravenous (2 and 4 mg/kg) and intraduodenal (12.5 and 25 mg/kg) administrations, dose-dependently abolished the rhythmic bladder contractions in anesthetized rats. The activity of HY-770, in intravenous administration (i.v.), was almost equal to those of flavoxate, terodiline and oxybutynin; and the activity of HY-770, like terodiline, was more potent than that of flavoxate in intraduodenal administration (i.d.). 2) In the cystometrograms, HY-770 (3, 4 or 8 mg/kg, i.v.) dose-dependently increased the time to micturition (capacity of bladder) without decreasing the amplitude of micturition contraction in anesthetized rats, dogs and cats, and HY-770 (25 mg/kg, i.d.) also increased the capacity in anesthetized cats. 3) HY-770 (4 and 8 mg/kg, i.v.) dose-dependently increased the capacity of the bladder in the cystometrograms of pollakiuria induced by either transection of both the hypogastric nerves or chronic cannulation to the bladder in anesthetized or conscious rats, respectively. 4) HY-770 (25 mg/kg, i.d.) slightly decreased the urethral pressure in anesthetized dogs. These results suggest that HY-770 is a promising drug for the treatment of pollakiuria induced by a neurogenic bladder or unstable bladder, etc.
