French researchers say they have found in the venom of the deadly African black mamba, a painkiller that is as powerful as morphine but without most of its adverse side-effects.
Black mambas are one of the largest and most feared venomous snakes widely distributed in sub-Saharan Africa. The toxin which, according to Arstechnica, contains a powerful neuro- and cardio-toxin, causes paralysis and irregular heartbeat. It shuts down organ function and kills a human victim within six hours if an antidote is not administered in time.
Recent tests on mice show that the black mamba venom also contains a substance that has been identified as a potential painkiller, the journal Nature reports.
According to the BBC, researchers are trying to understand why the mamba would produce a painkiller. Dr. Eric Linguelia of the Institute of Molecular and Cellular Pharmacology, said researchers are surprised that black mamba venom would contain such a powerful painkiller because the mamba is notorious for its aggressive killer instincts. Wired.com reports that black mambas are known to attack animals as large as lions and leopards in defense of their territory.
According to the Smithsonian Magazine,
"In Africa, when it’s necessary to take down fearsome black mambas... locals must band together. The mambas are known to explosively strike in all directions, while raising a third of their 10-foot-long bodies into the air. Their venom, delivered through its black-colored jaws, is known to be some of the most potent in the world."
According to the journal Nature, the researchers examined venom from about 50 species, including the black mamba venom, to identify inhibitors of acid-sensing ion channels (ASIC) that appear on the surface of nerve cells involved in ability to sense pain. According to Wired.com, injury produces certain acid chemicals which the brain interprets as pain and ASICs are central to the process of detecting a rise in acidity that leads to pain sensation.
The researchers isolated proteins in the mamba venom which they called mambalgins. Mambalgins inhibit acid-sensing ion channels (ASIC) in the brain and sensory nerves in the peripheral system. The effect is an analgesic function comparable to morphine.
According to the research abstract published in the journal Nature, mambalgins are a new class of,
"...three-finger peptides from... the black mamba... able to abolish pain through inhibition of ASICs expressed either in central or peripheral neurons... mambalgins, are not toxic in mice but show a potent analgesic effect upon central and peripheral injection that can be as strong as morphine... mambalgins cause much less tolerance than morphine and no respiratory distress."Arstechnica reports the authors say mambalgins are "powerful, naturally occurring, analgesic peptides of potential therapeutic value."
The BBC reports that Dr. Eric Linguelia, said: "When it was tested in mice, the analgesia was as strong as morphine, but you don't have most of the side-effects."
According to Linguelia, morphine acts on the so-called opioid pathway in the brain to cut pain. However, one of the adverse side-effects of morphine is that it is addictive. It also causes headaches, difficulty in thinking, vomiting and muscular twitches.
According to the researchers, mambalgins relieve pain in a different way which they believe should not produce the adverse effects of morphine. Arstechnica reports the authors argue that mambalgins indicate the possibly of a previously unidentified pathway in the brain that relies on a specific combination of ASICs.
Animal testing revealed that mambalgins "do not produce motor dysfunction, apathy, flaccid paralysis, convulsions or death upon central injections," Gizmodo reports.
Linguelia also explained that tests on mice is relevant to humans because the biochemical processes through which pain works in humans are similar to how they work in mice.Tests carried out on human cells in the laboratory using mambalgins have similar effects as in mice. The researchers, therefore, believe they can develop from mambalgins new effective painkillers for human use.
Linguelia said: "It is the very first stage, of course, and it is difficult to tell if it will be a painkiller in humans or not. A lot more work still needs to be done in animals."
The BBC reports that Dr. Nicholas Casewell, expert in snake venom at the Liverpool School of Tropical Medicine, who has recently emphasized the potential of venom as drug source, commented on the new study, saying: "It's very exciting, it's a really great example of drugs from venom, we're talking about an entirely new class of analgesics."
Casewell agreed with Linguelia, saying it was "really, really odd" that mamba venom would contain a painkiller. However, he suggested that the painkiller may work "with other toxins that prevent the prey from getting away." He also suggested that it may have different effects on different animals that the mamba preys upon.
Dr. Roger Knaggs of the Royal Pharmaceutical Society, said: "We are witnessing the discovery of a novel mechanism of action which is not a feature of any existing painkillers." However, he said that further development was required before the substance can be used in people.
ABC News reports that Dr. Michael Roizen, an internist and anesthesiologist at the Cleveland Clinic, said that if mambalgins are shown to be effective for relieving severe pain without any of the adverse effects of morphine, then “it would be a major advancement.” He added: “It’s a new avenue, a new approach to therapies. You’d love it to work.”
According to National Geographic, venom from snakes, spiders and scorpions have been used for centuries by traditional cultures for medicinal purposes. Recently, scientific research has focused on developing venom for use in the pharmaceutical industry. National Geographic reports "aspects of king cobra, copperhead, rattlesnake, and viper venom have been found to have an effect on a wide range of medical maladies, ranging from the dissolution of blood clots to possibly slowing the growth of cancer cells."