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Viagra (Sildenafil citrate) OnlineTreatment of erectile dysfunction (ED)
The first breakthrough in the treatment of erectile dysfunction occurred in 1983. It was thought before that the inability of erection is caused mainly mental health problems.
But in 1983 at a meeting of the American Association of Urologists Dr. Giles Brindley demonstrated the possibility of obtaining an artificial erection by injection of phentolamine
It was a memorable one. The doctor showed an injection and the result is right on the stage.
What did phentolamine? He loosened the muscles. To understand how this has affected the erection, we have to pay attention to different kinds of muscles in our body.
There are three types:
- Skeleton - these muscles are clearly visible in the bodybuilding competition.
- Heart - it is the muscles that move the heart.
- Smooth - Smooth muscle can be found, for example, in blood vessels, stomach and intestine. Usually, they act spontaneously.
Smooth muscle plays a key role in erection, and phentolamine relaxes them. Here's what happened in 1983 at a meeting of urologists:
- Unexcited penile arteries are narrowed and do not let blood get into the cavernous body.
- Injection of phentolamine relaxed smooth muscles of the arteries inside the penis, causing them to open.
- Blood filled the cavernous body and its pressure get an erection.
Thus, from mid-1980's erectile dysfunction treated with injections of smooth muscle relaxants. But then came Viagra and everything changed.
The advantage of tablets over injections is obvious, but there was also a major difference in the action. Phentolamine caused an immediate and uncontrollable erections. Viagra also causes an erection but only in the case of sexual arousal.
How did tablet can relax the smooth muscles in the penis only, and not throughout the body, and only in the case of sexual arousal? To answer this question we have to consider the circulatory system.
Blood circulation and Viagra
How can I get an erection with the help of pills? Phentolamine's not ideal, because it will relax all smooth muscles of the body, and it will cause serious problems. It is necessary to create a drug that acts solely on the smooth muscles of the arteries in the penis.
We'll have to learn more about blood circulation.
So, we all know that the heart is like the pump is pumping blood throughout the body. But different parts of the body require different amounts of blood at different times.
For example:
- If you have a nourishing meal, the body must send more blood to the stomach and digestive tract.
- If you run a marathon, your body is required to send more blood to the muscles of the arms and legs, while the delivery of blood to the stomach is significantly reduced in order to save oxygen for the feet.
In other words, the body needs a whole set of valves for the regulation of blood flow in certain parts. The brain, respectively, requires control over it to open and close it if needed.
The penis is one of those parts of the body with a valve which regulates the brain.
How?
Now tell.
Open and close valves
In the human body "valves" are opened and closed by muscles in the walls of arteries. When muscles are relaxed - the artery open and blood flow increases. This happens in response to chemical signals, controlled by the brain. This mechanism can be divided into four steps:
1. The brain sends a signal to a particular nerve fiber. The fiber ends NANC nerve cell in the artery near the point where you want to change the bloodstream. NANC means «nonadrenergic-noncholinergic», which means that this cell can produce nitric oxide.
2. NANC injects nitrous oxide in the blood and surrounding cells.
3. Nitric oxide stimulates an enzyme called guanylyl in neighboring cells and this enzyme starts producing a chemical compound called cyclic guanosine monophosphate (cGMP).
4. cGMP causes the smooth muscles in the arteries to relax, which increases blood flow.
The enzyme phosphodiesterase (PDE) deactivates the cGMP. cGMP is made up unless there is a signal from the brain. As soon as it stops, the effect gradually disappears as a result of the PDE.
The valves work in our body that way. How does this relate to the erection?
The main cause of erectile dysfunction (especially related to age) is the lack of development of cGMP. The signal comes from the brain, cGMP is produced, but not enough to open up the artery. The problem is recognized, it remains to decide how to create a drug acting exclusively on the valve in the penis.
Treating ED with Viagra
So, based on the fact that we have learned, we can define three ways to increase blood flow to the penis:
1. Increase the number of nitric oxide in the penis
2. Increase the number of cGMP, produced in the penis in response to nitric oxide
3. Reduce the amount of PDE in the penis to allow cGMP to reach the required number without decomposition
Viagra uses the third method. The reasons for this are in the same interesting features of PDE.
The human body produces at least 11 different types of PDE, and only one of them (PDE5) can mainly be found only in the penis. Once this was discovered, the invention of Viagra has ceased to be a problem.
It remains to find a chemical that blocks only PDE5. In this case, the impact on other parts of the body is reduced to a minimum.
How does
Viagra blocks PDE5?
PDE5 is an enzyme, and the enzyme is a protein folded in a special way and accelerating the chemical reaction. For example, an enzyme Maltase is shaped so ideally suited to a molecule of maltose. Once the molecule is joined to him, an enzyme breaks it into two molecules of glucose.
PDE5 is an enzyme that connects to cGMP and breaks it. It was necessary to find a substance that would be glued to the PDE5 and blocked his work. This substance is sildenafil citrate. It is contained in the tablets of Viagra.
When you receive Viagra sildenafil citrate passes through the body, affecting only the enzyme PDE5. The drug remains in the blood approximately four hours and then removed from the body by the liver and kidneys.
Thus, the total scheme of Viagra is as follows:
• A man takes Viagra.
• Sildenafil citrate enters the bloodstream and spreads throughout the body.
• Sildenafil citrate joins the enzyme PDE5 and destroys it.
• In the event of sexual arousal the brain sends a signal to NANC cells in the penis and stimulates the production of nitric oxide.
• Nitric oxide creates cGMP, which relaxes the arteries in the penis.
• Because PDE5 is not working, cGMP does not decay, accumulates and allows the arteries to fully open.
• The blood fills the cavernous body, and a man gets an erection.
It works in most cases.
How Does Viagra Work Part 1
