Nitric oxide (neurotransmitter): definition and functions

Some of you might think that nitric oxide is a laughing gas, better known as "laughing gas." Well, that's nitrous oxide (N2O).

In this article we will talk about nitric oxide, also called nitrogen monoxide or NO It is a fat-soluble gaseous molecule that acts as a neurotransmitter in the brain and carries out different functions within our body.

Since its discovery, nitric oxide has become one of the most studied molecules in human physiology. Studies confirm the natural ability of nitric oxide to prevent clotting, regulate inflammation, revitalize tissues, improve erectile dysfunction or kill invading microorganisms and even eradicate cells cancerous.

• Related article: "Cancer types: definition, risks and how they are classified"

In addition, nitric oxide promotes erection, and as a supplement it is consumed in the circuits of the sports training and bodybuilding, as it promotes resistance to fatigue and improves development muscular.

Nitric oxide characteristics

And it is that this gas has aroused great scientific interest. As early as 1970, an American doctor named Ferid Murad realized that nitrates used when people suffer from chest pain or cardiovascular problems release rust nitric, well

this substance has a dilating effect on the blood vessels and relaxes the muscle layer in the endothelium.

A few years later, in 1987, studies confirmed that the human body produces nitric oxide, which led to to investigate how it is formed, what it does and what are the functions of this compound within the body human. In 1998, the authors of these discoveries, Robert Furchgott, Ferid Murad, and Louis J. Ignarro, received the Nobel Prize.

How Nitric Oxide Is Synthesized

Nitric oxide is synthesized from the protein amino acid arginine and L-citrulline, a non-protein amino acid, thanks to the action of an enzyme called nitric oxide synthase (NOS). In addition, for synthesis to occur, the presence of oxygen and a coenzyme (an organic molecule that binds to the enzyme) is necessary. reduced nad-phosphate (NADPH). In most living beings, NO is produced in different types of cells.

• Do you want to know the types of cells that exist in the human body? You can do it by visiting our post: "Major cell types of the human body"

Functions in our body

In addition to the studies that I have mentioned before and that earned their authors the Nobel Prize, in the last three decades there have been more than 60,000 investigations carried out on this gas.

Nitric oxide plays different roles in both the central and peripheral nervous systems, among which stand out:

• Reduces inflammation and blood clotting
• Improves immune system performance by defending against bacteria and fighting cancer.
• Increases recognition of the senses (for example, smell)
• Increases endurance and strength and muscle development
• Has a positive effect on gastric motility
• It enhances sleep quality
• Improve memory

• Related article: "Types of memory: how does the human brain store memories?"

Nitric oxide as a neurotransmitter

Neurotransmitters are chemical molecules that send signals within the nervous system. Nitric oxide, being a gas, does not fit the classic definition of other neurotransmitters such as dopamine wave serotonin.

However, this gaseous molecule performs functions as a neurotransmitter and neuromodulator.

According to the authors Fernández-Álvarez and Abudara Morales, neurotransmitters, classically, should meet these requirements:

1. Should be present at presynapsis
2. It should be stored in the presynaptic terminal
3. Should be released by presynaptic nerve stimulation
4. Exogenous administration of the substance would elicit a response identical to that caused by nerve stimulation. presynaptic and drugs should elicit the same modifications in the response caused by nerve stimulation presynaptic
5. In the synapse there must be mechanisms that allow the end of the action of said neurotransmitter substance on the postsynaptic neuron

Since NO is a gas and its physico-chemical functions are different from other neurotransmitters, it does not meet all of the above criteria. However, this does not mean that it does not act as a chemical messengerRather, this type of transmission constitutes a particular form of transmission.

Generally, neurotransmitters are produced, stored, and used when required by the nervous system. Once these are used, an enzyme acts on them, in many cases, degrading them. In the case of NO this does not happen, as it does not occur in advance. It is synthesized when it is needed.

Furthermore, unlike other neurotransmitters, it does not have a localized effect, but diffuses in many directions and, being a gas, it can affect many cells. Therefore, although both classical neurotransmitters and NO send information, they do so differently.

• Would you like to know more about classical neurotransmitters? In our article "Types of neurotransmitters: functions and classification"We explain them to you.

Nitric oxide and its relationship with Viagra

Research on this gaseous compound has also concluded that nitric oxide is of utmost importance in male erection. In fact, the drugs used to treat erectile dysfunction act on the nitric oxide pathway that allows blood to flow to the male organ.

One of the best known drugs to treat this problem is Sildenafil, which you will surely know by its trade name: "Viagra". But what is the relationship between Viagra and nitric oxide? Well, when we think of having intimate relationships with someone or we are in a situation in which intimate stimulation occurs, nitric oxide is released in the nerve endings of the male organ.

This compound causes relaxation relaxation of the muscles, the dilation of the corpora cavernosa and the blood vessels in this area, and this relaxation allows blood to enter the arteries and, consequently, the erection. When nitric oxide moves into smooth muscle cells in blood vessels, it causes different chemical reactions by increasing the chemical messenger GMPc, this produces the dilation of the vessels that allows the flow of the blood. Once the cGMP has performed its function, it is degraded by the phosphodiesterase enzyme (PDE). Viagra blocks phosphodiesterase, thus preventing cGMP degradation and improving erection.