Hemodynamics of pelvic nerve induced erection in a canine model. II. Cavernosal inflow and occlusion.

Using a previously developed canine model of erection, we measured pudendal artery and venous flow as well as pressure in the corpora cavernosa, pudendal artery and vein. Penile erection was induced by pelvic nerve stimulation. Generalized arterial vasodilatation was dependent on stimulation frequency and occurred most prominently at stimulation frequencies of approximately 16 Hz. Cavernosal smooth muscle relaxation was also frequency dependent in a similar manner. In contrast, using a technique of delayed arterial inflow, we demonstrated that helicine artery relaxation was very sensitive to stimulation frequency and occurred only at a stimulation frequency of approximately 16 Hz. The mechanism of corporal occlusion is primarily dependent on nerve-induced relaxation of the cavernosal smooth muscle. The frequency-dependent nature of pelvic nerve induced erection is primarily due to the frequency dependence of the cavernosal resistance vessels that control arterial inflow to the cavernosal spaces.