Is Snail Saliva as Effective as Morphine?

To treat severe pain, a sea snail may hold an answer. Scientists have developed a new medication first isolated from sea snail saliva that may be as effective as morphine.

Sea snails may not move fast, but what they lack in speed, they more than make up for in chemicals. These animals have the ability to inject a mixture of toxins called conotoxins into their targeted prey using their needle-like teeth.

These conotoxins consist of peptides that can relieve severe neuropathic pain as effectively as morphine, but it does not lead to addiction. Attempts to transform these conotoxins into a drug that could be used as a pain reliever has been challenging. Thus far a synthetic version has been developed, but it must be injected directly into the spinal cord using an implanted pump.

Now, a team of scientists in Australia have developed a conotoxin that can be taken orally. In tests with rats, the new drug proved to be as effective a pain killer as gabapentin, which is the most popular drug to treat neuropathic pain. Compared with the dose of gabapentin needed to treat pain, however, the conotoxin-based peptide (named Prialt) is less than 1 percent.

The research team, led by David J. Craik of the Institute for Molecular Bioscience at the University of Queensland, noted that peptides have generally been regarded to be poor pain killers because they are not stable and mostly not available in oral form. One exception has been the immunosuppressant cyclosporine.

Could a drug based on sea snail saliva be next? Jon-Paul Bignham, a professor of molecular biosciences and bioengineering at the University of Hawaii, Manoa, pointed out that an oral drug that has the pain killer abilities of Prialt “would absolutely revolutionize how we manage chronic and terminal pain.” Move over, morphine.


Chemical & Engineering News 2010