The influence of vesical distension on urethral resistance to flow: the expulsion phase

The influence of vesical distension of the urethral pressure profile was studied in female dogs, using a model in which the bladder and urethra were separated. There was a reduction in the urethral resistance involving its smooth and striated muscle components. This reduction was completely blocked by ganglion blocking agents. Atropine did not influence these changes. Propranolol could only partially block this reflex. The other possible mechanisms that could be involved were discussed.