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Tarantula Venom May Block Chronic Pain

University of Queensland researchers have found seven peptides in tarantula venom that block the molecular pathway responsible for pain signals sent from nerves to the brain. The discovery, published in the British Journal of Pharmacology, could inspire a new class of painkillers with fewer side-effects than current medications.

Prof Glenn King said that the peptides block voltage-gated sodium channels, which play a key role in pain transmission. “Previous research shows people who lack Nav1.7 channels due to a naturally occurring genetic mutation are unable to experience pain, so blocking this channel could potentially help us to switch off pain in people with normal pain pathways,” King said.

“We have nine sodium channels in our bodies, and our challenge is to find peptides that can distinguish between these channels and target only Nav1.7 – something current pain relief drugs can’t do but spider venom peptides most likely can.”

Part of the search for new medicines has focused on the world’s 45,000 species of spiders, many of which kill their prey with venoms that contain hundreds or even thousands of protein molecules. Some of these molecules block nerve activity.

“A conservative estimate indicates that there are nine million spider venom peptides, and only 0.01% of this vast pharmacological landscape has been explored so far,” says team member Dr Julie Kaae Klint.

The challenge was to build a research method that could analyse this huge number of peptides to find candidates that both targeted Nav1.7 channels and had the necessary levels of chemical, thermal and biological stability required to be an effective medicine.

“We analysed venom from 205 spider species and found that 40% of the venoms contained at least one peptide that blocked human Nav1.7 channels,” King said. “Importantly, of the seven promising peptides we identified, we discovered one that had the right structure, stability and potency to form the basis of a future painkiller.

“Our next step is to continue exploring the clinical potential of these peptides – and the ones we are still yet to find – in the hope of developing better treatments for the one-in-five Australians living with persistent pain,” King said.