Viagra's Upcoming Competition: Brazilian Spiders

Brazil may soon be exporting more than waxes -- Brazilian spider bites appear to outperform Viagra, Cialis, and Levitra.  Effective -- yes -- but also painful.

In Brazil, emergency room staff can immediately spot the victims of a bite from the Brazilian wandering spider (Phoneutria nigriventer). Patients not only experience overall pain and an increase in blood pressure, they also sport an uncomfortable erection.

The erection is a side effect that everybody who gets stung by this spider will experience along with the pain and discomfort, said study team member Romulo Leite of the Medical College of Georgia. Were hoping eventually this will end up in the development of real drugs for the treatment of erectile dysfunction.

Leite and colleagues broke the venom down into its individual components. In what had to be an awkward series of experiments, they injected each component into rat penises until they found the culprit: a short amino acid sequence they dubbed Tx2-6, which increased nitric oxide in the blood holding region (corpus cavernosum) of the penis.

The significance of the nitric oxide is clear when the science behind an erection is considered: The brain senses sexual arousal in the body and certain neurons produce nitric oxide, a message telling the body to get started in making an erection. A cascade of biochemical steps occurs, one of which includes the production of an enzyme dubbed cGMP. This enzyme causes the smooth muscles of the penis two cylinders to relax so that blood can rush in and fill up the now expandable tubes. (A human penis can hold about 10 times more blood when erect compared with its non-erect state.)

All of this leads to vaso-dilation of vessels that go through the penis and also relaxation of those [cylindrical tube muscles], Leite told LiveScience. They need to relax so the blood will come inside and thats how you get an erection, because the blood gets trapped into the penis.

Instead of increasing cGMP levels like Tx2-6, Viagra, Cialis, and Levitra all work by inhibiting the action of an enzyme known as phosphodiesterase-5 (PDE-5); PDE-5 degrades cGMP, causing erections to fade away.

I wonder if this would be beneficial for women?