A huge, horrifying spider might be the last thing you want to think about in the throes of passion, but scientists are now using spider venom to cure erectile dysfunction.
Venom from the Brazilian wandering spider (Phoneutria nigriventer), also known as the banana spider, is the perfect candidate for a Viagra-like drug, as it is known to cause painful and long-lasting erections as a side effect.
"Priapism is a prolonged and painful erection, which can lead to necrosis of the penis", researcher Maria Elena de Lima, a professor of biomedicine and medicine at the Santa Casa Belo Horizonte hospital in Brazil, said in a statement.
Researchers are investigating the use of the venom in a drug to treat erectile dysfunction when Viagra does not work, or is not permitted due to health conditions.
Viagra, which contains the drug sildenafil, works by blocking an enzyme that makes the penis more sensitive to a chemical called nitric oxide. This nitric oxide causes increased blood flow to the penis, leading to an erection. The venom of the Brazilian wandering spider results in an influx of nitric oxide, therefore also leading to a painful and sustained erection.
Over several years of research, the Brazilian team isolated the active ingredient of the venom causing the erections, the molecule PnPP-19. The scientists then figured out how to make this molecule in the lab—naming the synthetic molecule BZ371A—and tested its effects on mice and rats when applied in a gel.
They found that this molecule did indeed trigger a release of nitric oxide, boosting blood flow to the genitals. It was also found to work in older rodents, and those with high blood pressure and diabetes, indicating that it may work for those demographics in humans too, who cannot use Viagra.
"We synthesized this molecule and began testing it on mice and rats, to check whether it would have the same effect as the original molecule, that is, the spider toxin. After in vitro tests, that is, in the corpus cavernosum isolated from mice, as well as in anesthetized animals, we observed that this molecule, much smaller and non-toxic, caused erections in these animals," de Lima said.
The researchers have subsequently trialed the gel in men and women, finding that it was successful, and also tested it in tandem with other drugs like Viagra.
"In both men and women, it caused an increase in blood flow in the inguinal region. This test was very important to demonstrate that the peptide had an effect on humans – it is worth remembering that the effect observed in animals is not always repeated in humans", de Lima said. "All of these tests helped to demonstrate that the peptide, like the toxin, releases nitric oxide, a common and fundamental neuromediator in the erection process. After administration of the peptide, there is a considerable increase in the release of this nitric oxide, which leads to the dilation of the corpus cavernosum and a consequent erection."
These trials also found that the new molecule caused no negative side effects in humans.
"The results from this phase, in fact, did not demonstrate any toxicity of the compound to humans. This is already a major advance, because there are very few drug candidates that reach this stage", de Lima said. "A very positive property of this solution, which was effective and which attests to its safety, is that the action is local, not causing systemic changes. In other words, it only has good local effects, with the absence of negative systemic effects.
In the second phase of trials, the drug will be tested on men with erectile dysfunction as a result of prostatectomy, and will be required to pass a third round of trials before it can be approved as a drug.
The researchers also hope to look into the drug's ability to increase blood flow to the genitals of women, and how it may be used to treat sexual dysfunction in the female body.
"The increase in local blood flow and vascularization has been proven in previous studies and could be an opportunity to be explored by Biozeus in the near future", Paulo Lacativa, a doctor and the CEO of Biozeus, the company currently developing the drug, said in the statement.
Newsweek has reached out to de Lima and Biozeus for comment.
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