Effects of pressoreceptor stimulation on micturition relfex and urethral pressure profile in rabbits

The influence of pressoreceptor stimulation on the micturition reflex and urethral pressure profile was studied. Stimulation of pressoreceptors of the aortic arch and carotid sinus causes an increase of parasympathetic tone and a decrease of sympathetic tone. Striated muscular tone was also decreased. Pressoreceptor stimulation was simulated by electrical stimulation of the depressor nerve in the rabbit. Our studies show that with pressoreceptor stimulation micturition occurred with 24 per cent less bladder filling and 32 per cent less intravesical pressure than before stimulation, and urethral pressure profile showed a 17 per cent decrease of the maximum and mean urethral pressure. The interpretation of the action of parasympathicomimetic and sympathicomimetic drugs on bladder and bladder neck must take into consideration the cardiovascular effects of these drugs and therefore the effect on the pressoreceptors.