Nitric oxide is a colourless, odourless toxic and non-inflammable gas. Nitric Oxide [(Nitric oxide (NO) should not be confused with nitrous oxide (N2O)or with nitrogen dioxide (NO2) ] is a small signalling molecule synthesized from the amino acid L-arginine by the family of nitric oxide synthases including eNOS (endothelial, NOS-III), iNOS (inducible, NOS-II), and nNOS (neuronal, NOS-I). The elucidation of nitric oxide as a signaling gas molecule resulted in the award of the Nobel prize in physiology/medicine in 1998, as this was the first time a gas molecule was identified to be produced by one cell, readily diffusing to another cell, and then acting as a signaling molecule in it. NO is synthesized in the body and subsequently released into the blood. NO is important for the β-adrenergic response of the heart. Upon β-adrenergic stimulation, the amount of NO in the cardiomyocyte increases.
Nitric oxide has been found to be produced by virtually every cell type in the body and plays an important role in controlling the normal function of cells as well as in regulating larger scale processes such as the nervous and immune systems. Nitric oxide is endothelial derived relaxing factor (EDRF). Healthy humans produce about 1 mM of
endogenous nitric oxide per day. It is produced in the endothelium of blood vessels and diffuses out of the cells. It then enters vascular smooth muscle cells and activates guanalate cyclase which forms cyclic guanosine monophosphate (cGMP)
Nitric oxide plays many important roles in the immune system. It is produced in high amounts from specialised cells of the immune system called macrophages. NO when inhaled, produces pulmonary vasodilation. NO is also important for mitochondrial respiration in the heart. NO stimulation increases mitochondrial oxygen consumption (MV̇O2).
It impacted in the human body in the following way:
- Cardiovascular System
- Relaxing blood vessels (lowering blood pressure)
- Healthy circulating blood cells
- Heart Function
- Nutrient exchange
- Respiratory Tract
- Increasing blood flow through the lungs
- Relaxing airways (asthma)
- Cellular Function
- Reducing cell death or turnover
- New blood vessel formation
- Immune System
- Regulates inflammation
- Improves infection fighting ability
- Nervous system
- Promotion of natural “rest state”
- Pain management
- Memory improvement
- Gastrointestinal Tract
- Enhanced metabolism
- Nutrient absorption
NO and NO-related drugs have been employed to therapeutic effect in a range of cardiovascular and central nervous system diseases where loss of NO signaling is believed to play a contributory role. As an inhaled gas NO has been approved in the US and in Europe for the treatment of pulmonary hypertension (PH) and associated respiratory failure of the newborn.
Natural Resources of NO
- Beets
- Spinach
- Garlic
- Citrus Fruits
- Pomegranate
- Nuts
- Watermelon
- Red Wine