Although feared by most humans, the scorpion may turn out to be a lifeline for those suffering from extreme pain. A new study suggests poisonous scorpion venom may be able to give humans an alternative to dangerous and addictive painkillers.
Researchers at Tel Aviv University are investigating a novel painkiller based on natural compounds found in the venom of scorpions. Department of Plant Sciences Professor Michael Gurevitz said the compounds have gone through millions of years of evolution and some show high specificity for certain components of the body with no side effects.
Most scorpions will sting a human only if provoked and only a few have venom that’s dangerous to people. All known species possess venom, which is mainly used to paralyze or kill prey. The eight-legged arthropods vary in size and are instantly recognizable due to massive claws at the head and a flexible, segmented tail with a stinger that’s carried in a forward curve over the back. Scorpion venom is either a hemotoxin that, in humans, causes swelling, redness and pain or a neurotoxin that may cause convulsions, paralysis, cardiac irregularities and death. Nocturnal hunters, most species are tropical or subtropical.
The venom is a mixture of compounds (neurotoxins, enzyme inhibitors) each not only causing a different effect, but possibly also targeting a specific animal. Each compound is made and stored in a pair of glandular sacs, and is released in a quantity regulated by the scorpion itself.
Peptide toxins found in scorpion venom interact with sodium channels in nervous and muscular systems and some of these sodium channels communicate pain, said Gurevitz. "The mammalian body has nine different sodium channels of which only a certain subtype delivers pain to our brain. We are trying to understand how toxins in the venom interact with sodium channels at the molecular level and particularly how some of the toxins differentiate among channel subtypes. If we figure this out, we may be able to slightly modify such toxins, making them more potent and specific for certain pain mediating sodium channels," he added. “With this information, engineering of chemical derivatives that mimic the scorpion toxins would provide novel pain killers of high specificity that have no side effects.”
An Ancient Chinese Practice
In his research, Gurevitz is concentrating on the Israeli yellow scorpion, one of the most potent scorpions in the world. Its venom contains more than 300 peptides of which only a minor fraction has been explored. The reason for working with this venom, he says, is the large arsenal of active components such as the toxins that have diversified during hundreds of millions of years under selective pressure. During that process, some toxins have evolved with the capability to directly affect mammalian sodium channel subtypes whereas others recognize and affect sodium channels of invertebrates such as insects. He says this deviation in specificity shows how toxins may be manipulated at will by genetic engineering.
While the use of scorpion venom to treat body disorders may seem counter-intuitive, the Chinese recognized its effectiveness hundreds of years ago. "The Chinese, as major practitioners of alternative medicine, use scorpion venom, believing it to have powerful analgesic properties," Gurevitz said.
Using an approach called rational design or biomimicry, Gurevitz is trying to develop painkillers that mimic the venom’s bioactive components. The idea is to use nature as the model, and to modify elements of the venom so that a future painkiller designed according to these toxins could be as effective as possible, while eliminating or reducing side effects.
An Alternative to Morphine
Finding a new and effective pain medication could solve one of the biggest problems in the medical world today. Pain is an important physiological response to danger, physical injury and poor health, yet doctors need to reduce extreme pain in some patients. While opiate-derived painkillers have been quite effective, the medical community is eager to find other solutions due to the risks associated with their use.
In clinical medicine, morphine is regarded as the gold standard, or benchmark, of analgesics used to relieve severe or agonizing pain and suffering. Like other opioids, morphine acts directly on the central nervous system to relieve pain. Morphine has a high potential for addiction; tolerance and both physical and psychological dependence develop rapidly.
"This new class of drugs could be useful against serious burns and cuts, as well as in the military and in the aftermath of earthquakes and natural disasters. Instead of running the risk of addiction, this venom-derived drug, mimicking the small peptide toxin, would do what it needs to do and then pass from the body with no traces or side-effects," said Gurevitz.
About the author: Pat Elliott is a journalist and blogger who has written about health issues for more than 20 years. She is also a cancer survivor who coaches people on how to manage their transition and take control of their new future.
Pat lives in Phoenix, Arizona where scorpion sightings are common and local parks even feature special evening tours to teach humans about the nocturnal lives and habits of scorpions. Strong, sturdy shoes are recommended for participants.