Physiology and pathophysiology of erection: consequences for present medical therapy of erectile dysfunction

Smooth muscle relaxation of the corpus cavernosum is the key mechanism of erection. It depends on a cascade of consecutive regulatory systems starting in the central nervous system, and proceeding via peripheral neurotransmission to intracellular signal transmission within the cavernous smooth muscle cells. Knowledge of these interacting mechanisms of erection is fundamental for understanding of the mode of action of new and possibly selective pharmacological agents that are presently available or under evaluation for treatment of erectile dysfunction.