A spider bite generally brings excruciating pain, but researchers from the University of Queensland in Australia suggest the venom of a South American tarantula could be put to better use.
By itself, tarantula venom can be toxic to humans, causing chest pain, breathing problems and anaphylactic shock. However, researchers discovered that a single peptide toxin found in the venom of Peruvian green tarantulas can be harvested to create more effective pain killers. The idea is that this peptide, called ProTx-II, can be used to target neural receptors in the brain to reduce the sensation of pain.
"Our group is specifically interested in understanding the mode of action of this toxin to gain information that can guide us in the design and optimization of novel pain therapeutics," Sónia Troeira Henriques, senior research officer at the University of Queensland's Institute for Molecular Bioscience, said in a news release.
Current pain relievers are not as effective as they should be. In fact, most are extremely addictive and pose a series of dangerous side effects. The hope, researchers say, is to improve the quality of life for the millions of people who suffer from chronic pain.
The team used 3-D imaging and molecular simulations to capture the structure of ProTx-II and determine how it would interact with the neuronal cell membrane to stop pain signals. They found ProTx-II inhibits Nav 1.7, an important pain receptor located on the cell membrane, and restricts its function.
"Our results show that the cell membrane plays an important role in the ability of ProTx-II to inhibit the pain receptor. In particular, the neuronal cell membranes attract the peptide to the neurons, increase its concentration close to the pain receptors, and lock the peptide in the right orientation to maximize its interaction with the target," Henriques added.
With further research the group hopes to refine the peptide toxin so that it binds with the cell membrane more readily and has fewer side effects or addictive qualities than most commonly used painkillers.
"Our work creates an opportunity to explore the importance of the cell membrane in the activity of peptide toxins that target other voltage-gated ion channels involved in important disorders," Henriques said.
Their findings were recently presented at the Biophysical Society's 60th Annual Meeting, which is currently being held in Los Angeles, Calif.
