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 waterinfusion 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.