Does bladder tone influence sensation of filling and electro-sensation in the bladder? A blind controlled study in young healthy volunteers using bethanechol

Purpose: The influence of bladder tone on filling sensation and electro-sen sation in the bladder was studied in young healthy volunteers. Materials and Methods: A total of 22 healthy volunteers 18 to 30 years old were included in our study, of whom 15 received a subcutaneous injection of 5 mg. bethanechol and 7 received a subcutaneous injection of water to serv e as randomly selected controls. In each group filling perception was evalu ated during medium fill cystometry before and 25 minutes after injection. T he bladder electrical threshold was determined in each group by constant cu rrent stimulation before and 25 minutes after injection. Results: In the study group there was a marked decrease in the volume at wh ich various filling sensations occurred after bethanechol was given. The pr essure at which all filling sensations mere perceived was higher after beth anechol than at baseline cystometry. The electrical threshold decreased wit h bethanechol. In the control group no change was noted in the perception o f filling or electro-sensation. Conclusions: Bethanechol has a distinct influence on the filling sensation and on electrical bladder stimulation. Each sensation is sharpened after th e administration of bethanechol. Several hypotheses are possible to explain these effects.