Researchers in Queensland, Australia, believe their work shows compounds in tarantula venom that may lead to more efficient painkillers.
Individual peptide toxins called ProTx-II, from the Peruvian Green Velvet tarantula, are being tapped to target receptors in the brain. Peptides bind to the Nav 1.7, an important pain receptor that transmits signals to the brain, and increase the amount of sodium ions moving across the membrane to prevent neurons transmitting pain. 205 species of spiders were studied and researchers found 40% of venom contained peptides that can block the Nav 1.7 pathway.
"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 optimisation of novel pain therapeutics," said Sónia Troeira Henriques, senior research officer at the University of Queensland’s Institute for Molecular Bioscience. Her recent work was published in the Biophysical journal on Feb. 16, 2016.
The group’s work is the first to describe the importance of the membrane-binding properties of ProTx-II for its potency as an inhibitor of Nav 1.7. "Until now, studies characterising the inhibitory activity of venom toxins have ignored the potential role of the cell membrane in their potency and activity," she noted.
The challenge for scientists is to isolate the painkilling peptide from the dangerous venom that can paralyze and kill its prey. If successful it could offer an alternative to conventional pain medicines that have soporific side effects and can be extremely addictive.
Image:Peptide toxin (blue) isolated from the Peruvian green velvet tarantula binds to neuronal cell membranes and inhibits the pain receptor NaV 1.7 (orange) at the cell membrane surface. Photo credit: Henriques