EFFECTS OF NERVE-STIMULATION ON BLOOD-FLOW IN THE URINARY-BLADDER, URETHRA AND PELVIC FLOOR IN THE DOG

Pelvic organs have triple innervation from the pelvic, sympathetic and pudendal nerves. Peripheral effects can be studied by neurostimulation of the nerves, whereas the topography of the spinal cord neurons can be determined by horseradish peroxidase tracing. We have evaluated the neurophysiologic effects of the nerves at their target organs by intraoperative electric stimulation and compared the effects to the anatomical innervation areas. These zonal areas were determined by blood flow alterations, measured with nine different microspheres. Pelvic nerve stimulation showed bladder contraction with no significant blood flow changes during stimulation. Sympathetic nerve stimulation caused moderate detrusor contraction and pressure increase in the bladder neck and intraprostatic area. Regional blood flow showed a four-fold increase in the bladder neck area during neurostimulation. Pudendal nerve stimulation revealed an intraurethral pressure increase with a 3.5-fold increase of blood flow in the sphincteric area and in the pelvic floor musculature.