Nitric Oxide's Role in Erectile Dysfunction
Erectile dysfunction is a common, multifactorial problem that can be caused by aging and a number of physical and mental conditions, such as high blood pressure, high cholesterol, diabetes, heart disease, and depression. A penile erection is a complicated process that involves both psychological and chemical factors as well as a noncholinergic, nonadrenergic neurovascular mechanism. Nitric oxide (NO) is thought to be the main neurotransmitter and chemical that causes a penile erection that doesn't involve adrenaline or choline. NO is released by nerve and endothelial cells in the corpora cavernosa of the penis. This turns on soluble guanylyl cyclase, which raises the amounts of 3′,5′-cyclic guanosine monophosphate (cGMP). As a second messenger, cGMP controls the activity of calcium channels and intracellular muscular proteins, both of which affect the relaxation of the smooth muscle in the corpus cavernosum. One of the main causes of erectile dysfunction is that NO doesn't w...