Scorpion venom provides clues for chronic pain and drug delivery
The toxin, produced by the Australian Black Rock scorpion, targets the ‘wasabi receptor’ – a sensory protein, also known as TRPA1, that is embedded in sensory nerve endings throughout the human body.
Upon activation, the receptor allows for the passage of sodium and calcium ions to flow into cells, which can cause pain and inflammation.
Commonly, this can be activated by chemicals in certain foods, such as onions, mustard, and wasabi – from which the receptor gets its name. However, it can also be activated by environmental pollution and cigarette smoke.
John Lin King, lead author of the study and doctoral student at UC San Francisco, explained, “Think of TRPA1 as the body's 'fire alarm' for chemical irritants in the environment."
He continued, “When this receptor encounters a potentially harmful compound -- specifically, a class of chemicals known as 'reactive electrophiles,' which can cause significant damage to cells -- it is activated to let you know you're being exposed to something dangerous that you need to remove yourself from."
The finding proved interesting to researchers due to the manner by which the ‘wasabi receptor toxin’ (WaTx) was able to enter cells. Dissimilar to many compounds, the sequence of amino acids that make up the toxin allows it to pass directly into the cell’s interior.
Lin King stated that this may allow further research to determine how this is possible before then using the peptides to carry drugs into cells that would normally struggle to pass through the cell membrane.
In further promise for the research, the investigators discovered that WaTx could instigate acute pain and pain hypersensitivities but without inflammation.
Lin King said, "This 'neurogenic inflammation' is one of the key processes that becomes dysregulated in chronic pain. Our results suggest that you can decouple the protective acute pain response from the inflammation that establishes chronic pain.”
This suggests that there is potential for drugmakers to target TRAP1 as a potential new avenue for treating chronic pain, away from opioid-based painkillers – which has become a greater focus in the pharmaceutical industry amid the ongoing opioid crisis.
This is not the first time that scorpion venom has been investigated for its therapeutic potential, with one set of researchers identifying one peptide that could be used to treat cancer.
