Objective: To examine the influence of autonomic receptor stimulation and blockade (noradrenaline, prazosin, terbutaline, propranolol, carbachol and atropine), and of pudendal nerve blockade on urethral stress relaxation.
Subjects and methods: Forty healthy women were evaluated. The stress relaxation parameter was defined as the relative rate of pressure decrease during a fixed period of time following a rapid dilatation of the urethra. The dilatation was performed by water-infusion into a small rubber cylinder placed in the urethra.
Results: The drugs did not affect stress relaxation significantly, whereas the pudendal blockade produced a significant change along the length of the urethra characterized by a faster pressure decay following dilatation.
Conclusion: In women, stress relaxation in the urethra relies significantly on the pudendal nerve-innervated striated muscles.