NITRIC OXIDE (NO)

NO's role in cellular function and disease

In the 1980s, NO was identified as a significant molecule that regulates a wide range of important cellular functions. Robert R. Furchgott, a member of our scientific advisory board, and two others were awarded the 1998 Nobel Prize in Physiology and Medicine for this discovery.

Recent research has also shown that NO also plays important biochemical and physiological roles in many diseases or medical conditions, including the following:

Cardiovascular Disease. The formation of NO in the cells that line the inner walls of blood vessels, referred to as the endothelium, has been found to play a crucial role in maintaining the dilation of the blood vessels, a process essential for the regulation of blood pressure. NO produced by the endothelium also inhibits the clumping of platelets, which are cells in the blood that promote clotting, and the adhesion of platelets and white blood cells to the blood vessels' inner walls, thereby significantly reducing the obstruction of blood vessels that is associated with blood clots and stroke. Numerous other cardiovascular actions of NO have been reported, including maintaining sufficient blood flow to the heart muscle and regulation of the contraction of the heart muscle. Cardiovascular diseases associated with NO imbalance include atherosclerosis, high cholesterol levels, high blood pressure, pulmonary hypertension and heart failure.

Gastrointestinal and Inflammatory Disease. NO is capable of influencing many of the biochemical and physiological reactions that are key to preventing or repairing injury to the gastrointestinal tract, such as stimulating mucus secretion from the mucus membrane lining the stomach and intestines and regulating the blood flow feeding the wall of the gastrointestinal tract and the mucus membrane. NO can control inflammatory cell activation and is active on other chemical mediators in the inflammatory process. Gastrointestinal diseases in which NO has potential beneficial actions include NSAID-induced gastric injury, inflammatory bowel disease, and peptic ulcer.

Central Nervous System Disorders. NO is also synthesized in nerve cells, or neurons, of the central nervous system, where it performs many physiological functions, including the formation of memory and the modulation of pain. NO-based therapies for diseases such as epilepsy, stroke, neuroinflammatory disorders and trauma may be able to provide protection to neurons.

Sexual Dysfunction. In the peripheral nervous system, NO is now known to play a role in regulating some forms of vasodilation and certain gastrointestinal, respiratory and genito-urinary functions. For example, male penile erection is dependent upon NO-relaxation of genital smooth muscles, and drugs like Viagra enhance the NO-signaling pathway.

Respiratory Disease. NO inhalation reduces pulmonary hypertension and improves oxygenation, the absorption of oxygen by the lungs. In inflammatory pulmonary diseases, such as asthma and chronic obstructive pulmonary disease, NO has potential to promote airway dilation and reduce inflammation, thus reducing airway sensitivity to airborne irritants and allergens.