A toxin in scorpion venom causes excruciating pain to victims in part because the slight acidity of scorpion venom aids in activating a pain pathway, according to a combined team of researchers from the U.S. and China. While scientists have extensively studied pain receptors, researching pharmacological tools and drug candidates, less is known about the specific mechanisms that underlie the acute pain associated with scorpion stings.
Much like other venomous species including spiders, snakes, and sea anemones, scorpions use a cocktail of toxins and their painful jabs deter much larger potential predators. One toxin, BmPO1, is known to target the TRPV1 ion channel to produce pain.
However, says the study in Science Advances, it emerged that BmPO1 activated the pain pathway at extremely high concentrations that don’t naturally occur in scorpion venom. The recent study found that the marginally acidic (at a pH of 6.5) venom allows it to donate subatomic particles called protons, which work in tandem with BmPO1 to “unlock” the TRPV1 ion gate and induce pain.