VIAGRA

I am sure after reading the label all of you must have got those naughty smirks on your face, specially the guys. To be honest even my inquisitiveness about viagra started for all the mischievous reasons, like any other regular college dude. As I read along about the "Blue pill", it made me realize that there is more to this pill than the adult overtones associated with it. My whole concept changed after I read an article which stated that it was a work which was awarded the Nobel prize for Medicine in 1998 that lead to the discovery of the drug. And I wondered was so great about the drug.

To begin its an exemplary example of how a signalling cycle which I read in biochem books was manipulated to give many men the wonder medicine for erectile dysfunction. Before that lets look at the process of erection. An erection begins with arousal. The brain detects the body becoming sexually aroused and transmits a message along the NANC (nonadrenergic, noncholinergic and uses nitric oxide to transmit the message) neuron to tell the body to begin creating an erection.  Once the nitric oxide reaches the neurovascular bundles near the prostate , an enzyme called guanylyl (soluble NO activated) cyclase is released. This enzyme converts GTP to cGMP. This causes the the relaxation of the smooth muscles lining the arteries of penis. The arteries dilate, filling the corpora spongiosum and cavernosa with blood.Then comes the part which most guys don't like- cGMP, however, is broken down by a second enzyme called phosphodiesterase type 5 or PDE 5. PDE 5 turns cGMP back into guanosine triphosphate or GTP to cause the arterial walls to not relax and decreasing the blood flow into the penis.

Discovery of viagra is serendipity at its best. Initially the drug was being tested on patients with cardiovascular diseases. But it did not work out that well, however one of the other effects of the drug was that it improved the erections in men. The whole focus of the clinical trial shifted in this direction now. The drug worked by inhibiting the enzyme PDE. It was originally developed by British scientists and then brought to market by the US-based pharmaceutical company Pfizer. It acts by inhibiting cGMP-specific phosphodiesterase type 5, an enzyme that promotes degradation of cGMP, which regulates blood flow in the penis. Since becoming available in 1998, sildenafil has been the prime treatment for erectile dysfunction. Never thought that studying Biochemistry could be so uplifting (pun unintended).