Any person, who read at least something about modern impotence pills, such as Viagra, Levitra and Cialis, met a word combination “PDE-5 inhibition” in their description. It is widely known that all these drugs are PDE-5 inhibitors and are used for treating erectile dysfunction in men. But what is PDE-5 and why is it so important to inhibit or suppress it in order to achieve firm and stable erection?

Before answering that question, let me remind one Eastern fairy tale about Aladdin’s lamp and paraphrase it in Sigmund Freud’s manner.

As you remember, Aladdin had a magic lamp, in which genie lived, who was big and mighty. In order to let the genie out, Aladdin had to rub the lamp and genie appeared, ready to fulfill any wish of his master.

It is amazing, but this story is nothing but a symbol of erection process. Judge by yourself – in order to get the erected penis (big and mighty genie), a man should be sexually stimulated (rub a lamp). When a wish is fulfilled (the sex was great), genie should be sent back inside his lamp.

A magic spell was the only means for Aladdin to control genie and send him back home. Approximately the same role in erection process belongs to special enzymes, called phosphodiesterase type 5 or PDE-5.

Now let us add a bit of science to the description of PDE-5 role in erection, because it is necessary for Eastern legend to have a bit of alchemy. So, normal erection process chain looks like this:

• when a man is sexually stimulated (kissing, watching or touching female body), his brain starts to send signals to penis with a command to get ready for sex;
• nerve endings in penis release nitric oxide (NO), which activates the production of cyclic guanosine monophosphate (cGMP) in corpora cavernosa (two spongy tubes in penis, which can expand and become firm when filled with blood);
• cGMP relaxes smooth muscles in small arteries and allows blood flow into the penis, providing its erection;
• now it is a high time for GREAT SEX;
• after ejaculation and the end of the sex act, PDE-5 enzymes appear on stage and destroy cGMP molecules;
• blood flows out of penis through veins and erection stops.

Thus, the quality and duration of erection is directly dependant on activity of PDE-5 enzymes. When they appear too early – a man is not able to maintain erection; when they kill cGMP molecules at the very beginning of the process, the erection is impossible to start.

The discovery of this chain of reactions or pathway in late 90th of the 20th century opened a road for its author to Nobel Prize and for Pfizer Company – a road to world leadership in production of the first PDE-5 inhibitor to treat erectile dysfunction.

Viagra, as well as its modern rivals – Levitra and Cialis, inhibits or slows down the activity of PDE-5 enzymes, allowing men’s genie go out and be ready to fulfill his mission.

However, it is important not to abuse PDE-5 inhibition, because everything should be balanced in nature. There is time to call for genie from the lamp and there is time to send him back after the mission is completed.

That is why impotence pills help only control PDE-5 enzymes, but not destroy them completely. Just imagine how many troubles and inconveniences could genie bring to Aladdin without a magic spell to send him back into the lamp...:)

P.S. When using Viagra, do not forget to rub a lamp at first to let your genie out…

Nick