You might hate (or love) spiders, but they’re actually great contributors to modern medicine. A new study on tarantula venom has provided researchers with insights on pain, which could eventually lead to better drugs for migraines or irritable bowl syndrome.
An international team of researchers, including neurophysiology experts from the University of Queensland, Flinders University, and the University of Adelaide, used a toxin from the venom of the Togo starburst tarantula (Heteroscodra maculata) to identify proteins on nerve fibres involved in pain signalling. The study was published today in Nature.
The findings are significant because the toxin can be used to model drugs able to bind to these proteins and block their action, helping to develop new therapies for conditions involving certain types of pain.
Specific types of pain
“We have found that there are specific populations of nerve fibres that innervate the skin and some are especially active when you have mechanical stimulation,” co-author Dr Volker Herzig, a neurotoxin expert from the University of Queensland, tells SBS Science.
Mechanical stimulation means getting physically hurt, like when stubbing your toe – this pain is registered differently from pain caused by burns, or that caused by chemicals (such as rubbing a wound with alcohol).
“So when you have chemical stimulation or thermal stimulation, like cold or heat, [these fibres] are not active – they’re only active when mechanically stimulated,” says Herzig.
The researchers used the spider venom toxin to stimulate pain in mice and found that it activated a specific nerve receptor that signalled this type of mechanical pain without triggering thermal pain.
According to Herzig, that abnormal signalling from this receptor has been shown in patients with epilepsy and irritable bowl syndrome, so a better understanding of how mechanical pain works could help to design an ‘anti-toxin’ as treatment.
“You could look for a toxin that does the opposite, so it specifically blocks this [receptor], and that could actually be useful as a drug,” says Herzig.
Towards precise pain treatment
Scientists have increasingly been looking into toxins from plant and animal venom – such as from the sting of blue-bottle and box jellyfish – as models for understanding how pain works.
Dr Irina Vetter, a neurophysiology expert also from the University of Queensland, says the findings could help to develop drugs that target specific types of pain.
“It’s a very elegant study and very exciting, we’re beginning to understand the different channels that contribute to different pain modalities,” says Vetter. “It also highlights the great potential of these venoms to delineate mechanisms of pain as they’re such selective tools – they can provide great insight for future treatment approaches for pain.”
Many drug therapies currently used to treat pain, such as the opioid drug morphine, are viewed as blunt tools that are not specific to pain types and often have dangerous side effects.
“There are obviously different targets that we haven’t even appreciated to date, and the approach that we’ve been using to use opioids to treat all types of pain is clearly an outdated approach,” says Vetter.
“What this toxin has shown is that we really just need to use very specific approaches for different types of pain.”