The Marine Snail that Could Help with Chronic Pain
Scientists from the University of Queensland have claimed they have come up with a painkiller that could be 100 times more effective than morphine, that would be perfect for combating chronic pain, and have presented their findings at the National Meeting and Exposition of the American Chemical Society (ACS) in Dallas, Texas.
So far, the team have come up with five new substances that are based on tiny proteins, or peptides, from cone snail venom. They believe that the substances can be developed into safe and effective oral medication for patients suffering with chronic pain.
Cone snails are carnivorous marine animals that inject their venom into their prey, which paralyses it long enough for it to be gobbled up. Animal venom is a poison that block certain channels of the nervous system. The ‘best’ painkillers, like morphine or hydrocodone, tend to come from opiates, and carry the huge risks of addiction or death from overuse.
The cone snail venom, on the other hand, contains hundreds of peptides called conotoxins which, according to the scientists, have a pain-relieving effect in humans. At the moment, only one drug, ziconotide, based on conotoxin has been approved for human use in medication. Unfortunately, this medication is not available in pill form, and so cannot be taken orally. Instead, it is administered at the base of the spine, which is obviously a highly invasive procedure.
Study lead, Professor David Craik from the University of Queensland in Australia explained that acute pain is the result of the nervous system being stimulated by an injury or wound, but chronic pain occurs when the nervous system itself has been damaged. This type of pain can last for a very long period of time, anywhere from months to decades, but treatments around at the moment will only work on a third of patients.
Because of this, Professor Craik and his colleagues are working on developing new drugs derived from conotoxins that could be taken orally in pill form, and would prove more practical and less invasive than ziconotide for patients. The team also claim that this medication could prove to be up to 100 times more effective than morphine, or other opiate-based drugs.
The researchers were able to manipulate the conotoxin peptides to form looping amino acids chains, which prove to be extraordinarily stable, as well as resistant to the enzymes in the body.
“[Conotoxin-derived drugs] act by a completely different mechanism than morphine, so we think it has a minimal possibility of producing side-effects of that medication,” explained Professor Craik. “This is one of the big advantages of the drug.”
The prototype drug has been tested on laboratory rats with a small, single dose, and found that it appeared to reduce pain drastically as measured by standard protocol. This is what led the team to conclude the potency of the drug versus that of opiate painkillers. And because the conotoxins act on different receptors in the brain, addiction would be less of a concern.
Professor Craik pointed out that the studies were still in the early stages and that human trials were at least two years away. Though, this does mean that potentially we could be looking forward to a potent painkiller that doesn’t carry such a high risk of addiction or other horrid side effects that need their own treatment, and this is positive news indeed.