Objective: The present study reviews the mechanism involved in the initiation and maintenance of penile erection.
Method: The study reviews the literature on the basic concepts supporting either "magically" or scientifically the erectile mechanism. An anatomo-physiological update is also included (i.e., the main neurological, muscular, and vasculoendothelial phenomena).
Results: Present studies based on the vasoactive action of different drugs have increased the knowledge on the neurological, muscular, and vasculoendothelial phenomena. The cavernous muscular relaxation may start and finish due to the equilibrium between the contractile adrenergic and the relaxing non adrenergic-non cholinergic stimulus through intracellular nitric oxide synthesis. This is an essential phenomenon involved in the entry and "trapping" of blood within the sinus spaces.
Conclusions: Our knowledge on the erectile mechanisms through neuromediators is increasing. The role of the endothelium in intracellular nitric oxide synthesis and its relaxing effect, will improve our understanding of both physiological and therapeutic phenomena.