“…The different penile structures receive autonomic (sympathetic and parasympathetic), somatic, and sensory innervations [2]. The autonomically innervated corpora cavernosa is composed of numerous nerve terminals, such as adrenergic, cholinergic, nonadrenergic, and noncholinergic innervations, and numerous neurotransmitters, such as acetylcholine, norepinephrine [3,4,5], adenosine 5'-triphosphate (ATP) [6,7,8], and nitric oxide (NO) [9,10,11,12,13]. The neurotransmitters released from the cavernous nerve terminals, as well as from the endothelial cells of the penis, have vasodilator properties and act to relax the arteries that supply the erectile tissue.…”