ABSTRACT
Nitric oxide is produced in high amount from the break down of arginine by a group of enzyme called nitric oxide synthase. Nitric oxide is an intercellular messenger that has been recognized as one of the versatile player in the immune system. Cells of the innate immune system such as macrophages, neutrophil and natural killer use pattern recognition receptors to recognize the molecular patters associated with pathogens. The specific role nitric oxide plays depend on the place of its release which in the immune system inhibits the replication of bacteria.
INTRODUCTION
Nitric oxide (NO) was among the first gas to be discovered in 1772, two years after the discovery of oxygen (O2) by the renowned Joseph Priestly.
Bogdan, (2000) defined nitric oxide as a free form gas that is produced in the body and is used by the body to communicate to other cells in the body. For more than two centuries this colorless and odorless gas was considered highly toxic. It is formed from nitrogen which comprises 80% and 20% oxygen of air. A highly reactive compound, it only exists for 6 to 10 seconds inside the body, then it is converted by oxygen into other compounds of nitrogen called nitrites. Uniquely, it is one of the few compounds with an odd number of electrons thereby making it a free-radical prone to ionizations. As one of the simplest compounds in nature, nitric oxide had been overlooked as an important factor to the body’s chemistry. Due to recent exposure however, thousands of new studies are being conducted concerning its application such as the role of nitric oxide in helping our immune system fight disease has been established (Bredt and Snyder, 1992). When our body notifies the immune system of an invader, our system uses other compounds to create nitric oxide. The nitric oxide in turn allows the macrophage S3 to devour such invaders as bacteria, Fungi and tumour cells (Bredt and Snyder, 1992). Nitric oxide has also been identified as a “messenger molecule” (Bredt and Snyder, 1992). In 1987, scientist working independently of each other in California and in England first revealed nitric oxide as a neurotransmitter. They were trying to identify the compound that caused the layer of cells that line the heart and blood vessels to relax. Finding that when the neuro-chemical acetylcholine 4 hit the surface of these cells released nitric oxide, scientists observed the relaxation of the muscle adjacent to the layer of cells. This discovery led to new breakthroughs toward better treatment for angina, hypertension and other serious heart problem. Nitric oxide since it is new understood to be the principal regulator of blood pressure (Quitab, 2003) is leading the old drug nitroglycerine in related breakthroughs.
The research was carried out in order to find out the functions nitric oxide carry in out body. It also shows how versatile the compound is which helps in carrying its specific roles.