Filling of the sinusoidal spaces with blood due to smooth muscle relaxation results from
parasympathetic neural pathway activation and probably simultaneous inhibition of
sympathetic outflow. The final common pathway for proerectile fibers is represented by the
cavernous nerves and fibers controlling detumescence and flaccidity originating in the
sympathetic chain. The hypogastric nerve could represent an accessory proerectile pathway
unmasked by a sacral spinal cord lesion. Nitric oxide, which can be colocalized with VIP and …