In vitro contractile responses of human detrusor smooth muscle to oxytocin: does it really have effect?

Background and objectives: The aim of this study was to investigate the contractile effects of oxytocin (OT) in human detrusor muscle in in vitro conditions.

Material and methods: Human detrusor muscle samples were obtained from seven patients that undergone radical cystectomy. Four female Wistar rats' uterine samples were used as control. Contractile responses were tested of carbachol in organ bath. Cumulative concentration response curves were constructed to OT and then the strips were incubated with atosiban (OT antagonist) and a second concentration response curve to OT were constructed.

Results: Carbachol, contracted all human strips for the functionality test whereas OT in any concentrations did not produce significant contraction on all human strips. In only one bladder strip and in a very high concentration slight contraction was recorded. Moreover no contractile response was recorded in any OT concentrations in the presence of atosiban. The rat uterine strips responded to OT in a dose dependent manner. Atosiban, the OT receptor antagonist diminished totally those contractile responses.

Conclusion: It is been demonstrated here that there is no contractile response to OT in human detrusor muscle. These findings should be supported by further investigations determining the presence of the OT receptor in human detrusor.