Hemodynamics of pelvic nerve induced erection in a canine model. I. Pressure and flow.

Using a previously developed canine model of erection, we measured pudendal artery and venous flow as well as pressure in the corpora cavernosa, glans penis, pudendal artery and vein. Penile erection was induced by pelvic nerve stimulation. Arterial flow increased by a factor of 2.5 within two seconds after the onset of stimulation. This was followed by a similar increase in venous flow about one second later. Spongiosal pressure began to rise about six seconds after nerve stimulation and always remained below cavernosal pressure. Cavernosal pressure began to rise after a latency of about 11 seconds. This latency period is accounted for by relaxation of the smooth muscle of the cavernosal sinusoids. Spongiosal pressure is maintained primarily by a high flow state through the glans penis while cavernosal pressure depends on a veno-occlusive mechanism.