We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Nitric Oxide Synthase?

By M.J. Casey
Updated Mar 03, 2024
Our promise to you
The Health Board is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At The Health Board, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Nitric acid (NO) is a small molecule with a double covalent bond between nitrogen and oxygen atoms. It is produced in the human body by a two-step synthesis from the amino acid arginine, catalyzed by the enzyme nitric oxide synthase (NOS). NOS is present in three forms in different tissues. The highly reactive NO is produced as a stress response and is both a cytotoxin and a cytoprotective agent.

A free radical, nitric oxide has toxic effects on host and bacterial cells. Its production in epithelial cells is controlled by epithelial nitric oxide synthase (eNOS). Nitric oxide synthase is bound in the cell’s membrane on the cytoplasm side or in the membranes of various organelles. NO in epithelial cells is instrumental in controlling vascular contraction and dilation. Anchoring eNOS in the cell membrane helps the cell restrict the activity of NO to small sites.

Inducible nitric oxide synthase (iNOS) is employed by the body to stall the growth of cells in gastric epithelial, breast, and brain tumors. NO made by the action of iNOS disables energy metabolism by reacting with the cell’s deoxyribonucleic acid (DNA) and ultimately kills the cell. Good tissue may be injured in the fight to kill tumor cells. Likewise, NO synthesized with eNOS fights the invasion of bacterial cells while indiscriminately killing surrounding somatic cells. Either type of host cell death can lead to toxic shock, a serious complication for patients with compromised immune systems.

In and around nerve cells, NO acts as a short-term signal transmitter, diffusing easily across membranes. Neuronal nitric oxide synthase (nNOS) is continuously recycled to produce NO, as the NO is stable for mere seconds before being neutralized by water molecules. The expression of the enzyme is regulated by calcium ion concentration. NO is believed to be involved in the conversion of short-term to long-term memory through a process called long-term potentiation (LTP).

Inhibitors of nitric oxide synthase are neuroprotective, as they reduce the availability of the free radical NO. Compounds in this class include hydrophilic vitamin C and hydrophobic Vitamin E. These and other molecules have been investigated with the hope of slowing neurodegenerative conditions such as Parkinson’s disease. As of 2010, direct links have not been demonstrated. One fear is that by decreasing the activity of nitric oxide synthase, neurons may be protected but memories may be lost.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Related Articles

Discussion Comments
The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.