(Phys.org) —A combined team of researchers from the U. S. and China has figured out why scorpion stings are so painful. In their paper published on the open access site Science Advances, the team explains how scorpion venom…
Scorpions have stingers on the ends of their tails that pierce the skin of victims and inject venom. Prior research has suggested the purpose of the venom is not to kill, but to cause pain so that predators will leave them alone. In this new effort, the researchers studied the venom and revealed why it is so painful.
They focused on a peptide called BmP01, previously identified as the most likely pain-causing ingredient in the fluid mixture of more than 100 toxins. Prior research has shown that it activates a pain signal carrying pathway in the brain called TRPV1. But what has confused prior researchers is why the peptide causes so much pain—on its own, it would not seem that the minuscule amount would be able to cause much pain. To find out what might be boosting its pain potential, the researchers looked at other ingredients and characteristics of the venom.
They noticed that the venom was mildly acidic. Looking even closer, they found that BmP01 tends to bind with proton-binding sites on TRPV1. Also, more importantly, the acid in the venom resulted in donations of protons that worked with BmP01 to heighten the amount of pain it could cause. Together, the researchers found, the two were able to unlock the gate that led to the TRPV1 pathway, which allowed more pain signals to pass through. That meant that the pain signals generated by the introduction of BmP01 into the body were magnified due to the acidity of the venom.
The researchers note that inflicting pain as a survival mechanism by the scorpion suggests that there may be more than one toxin in the venom that is being enhanced by donated protons, adding up to the very painful experience reported by victims.
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