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Cone Snail Venom Facts and Potential Medical Benefits

Linda Crampton has an honors degree in biology. She is very interested in plant chemicals and their actions and benefits in the human body.

What Are Cone Snails?

Cone snails are ocean predators with beautifully patterned shells. The snails produce a potent venom to paralyze their prey. The venom contains a complex mixture of substances that includes neurotoxins, which are chemicals that block the conduction of nerve impulses. At least one of these neurotoxins can sometimes relieve severe pain in humans. Researchers have also discovered that some species of cone snails produce a fast-acting form of insulin.

Scientists suspect that venom chemicals may be useful in many other ways besides the relief of pain. For example, specific chemicals may prevent epileptic seizures. A knowledge of cone snail insulin may lead to the creation of an improved treatment for diabetes. In addition, researchers are using the neurotoxins in the venom to learn about the functioning of our nervous system. These investigations may enable them to create new treatments for various diseases. The cone snail and its venom are intriguing.

More than 600 different species of cone snails exist. They all belong to the phylum Mollusca and the genus Conus. Most inhabit the warm water of tropical reefs. The snails have roughly cone-shaped shells, which gives them their name.

Diet and Respiration

Food Choice

Cone snails use their venom to catch their prey. They are divided into three groups based on the type of animals that they eat. One group catches small fish, another mollusks, and the third worms. Like other snails, cone snails move slowly. The exception to this rule is their equipment for catching prey, which moves impressively fast. The speed and the venom injected into the prey are essential in order for the snail to obtain food.

The Siphon and the Proboscis

The cone snail extends two tubular structures from its body, as can be seen in the videos in this article. The tube with the larger diameter is called the siphon. It takes in sea water, from which the animal extracts oxygen. The snail also detects chemicals released from its prey in the water. The tube with the smaller diameter is the proboscis. Food is taken into the body through this tube.

Catching Prey

Most mollusks have a radula, a ribbon-like structure in the mouth that is covered with tiny teeth made of chitin. The radula is used to rasp or cut food before it enters the esophagus. It’s sometimes likened to a tongue. The structure is highly modified in cone snails. Instead of a typical radula, they have a radular sac containing long, harpoon-like teeth. A tooth is shown near the start of the first video in this article.

When a cone snail has discovered a suitable food source, it slowly extends its proboscis towards the prey. The radular sac then releases a single tooth. The barbed tooth travels through the proboscis at high speed while still maintaining an attachment to the radular sac. The tooth stabs the prey and acts like a hypodermic needle. It has a hollow channel that contains venom transferred from a gland. The venom is injected into the prey, immobilizing it. The prey is then pulled through the proboscis and into the stomach.

The feeding process happens so fast that the method of catching prey is still being studied in order to understand all the steps, as is the anatomy of the structures involved. The feeding process is slightly different based on the diet of the snail, though radular teeth are always involved. Some fish-eating cone snails expand a hood-like structure from their proboscis in order to engulf their prey, as can be seen in the video below.

The geography or geographic cone snail is sometimes known as the cigarette cone snail. It's said that a person who has been poisoned by the animal's venom has time to smoke one cigarette before they die.

Features of the Venom

The smaller cone snails can give humans a painful sting but aren't dangerous. The bigger ones—which may be as long as nine inches—can be deadly for humans. They attack to defend themselves as well as to catch their prey.

Cone snail venom contains a complex mixture of many different chemicals. There are thought to be at least fifty to a hundred biologically active compounds in the mixture. There may be as many as two hundred compounds in some versions of the venom.

The venom contains conotoxins, also known as conopeptides, which are short chains of amino acids. Conotoxins quickly stop nerve impulses from passing between nerve cells or from passing from nerve cells to muscles. These actions cause paralysis in the snail's prey.

Potential Medical Uses of the Venom

Research into the properties of cone snail venom is making some exciting discoveries. At least some conopeptides are able to relieve pain, which they sometimes do very effectively. One kind is already being used as an analgesic (pain reliever) in humans and others are being tested. There may be many other uses for the chemicals in medicine.

Conopeptides are proving helpful in a non-clinical context as well. Each type seems to work by a very specific mechanism in the nervous system. Researchers are learning more about how the nervous system works with the aid of conopeptides.

The venom of each species of cone snail contains its own unique mixture of chemicals. This increases the likelihood that some of the chemicals may be useful to humans.

Ziconotide for Possible Pain Relief

After studying a conopeptide in the venom of a cone snail known as Conus magus, researchers made a synthetic version of the peptide. The artificial chemical, called ziconotide, has some useful properties. It has been approved as a medication in the United States by the FDA (Food and Drug Administration) and is in current use as an analgesic.

Ziconotide can sometimes be very effective at relieving pain, but its effects are variable. Some people say that the medication has been a wonderful help for them, some say that it produces only minor or partial pain relief, and others say that its benefits aren't worth the side effects that they experience.

Reportedly, ziconotide is not addictive. In addition, it doesn't seem to cause the development of tolerance in a patient. Tolerance is a state in which a medication that was once effective no longer works. The medication is sold under the brand name of Prialt.

Ziconotide is generally used only after other analgesics have been tried and have failed to work. It’s sometimes prescribed for people who are suffering from intense and prolonged pain, such as the pain that may be experienced by people with certain types of cancer or by people experiencing neuropathic pain.

How Does Ziconotide Work?

Ziconotide works by inhibiting the transmission of nerve impulses at synapses. A synapse is the region where the end of one neuron or nerve cell comes very close to the start of another one.

When a nerve impulse reaches the end of a neuron, it stimulates the release of a chemical called a neurotransmitter. This chemical travels across the tiny gap between neurons, binds to a receptor on the second neuron, and (in the case of an excitatory neurotransmitter) stimulates a new nerve impulse. Ziconotide inhibits the release of the neurotransmitter.

Structure of a Synapse

Ziconotide inhibits the voltage-gated calcium channels that are involved in synaptic vesicle movement. The vesicles normally release neurotransmitter molecules into the synaptic cleft.

Ziconotide inhibits the voltage-gated calcium channels that are involved in synaptic vesicle movement. The vesicles normally release neurotransmitter molecules into the synaptic cleft.

Ziconotide must be prescribed by a physician and administered by a medical professional. In addition, anyone taking the medication must be under a doctor’s care.

Potential Drawbacks and Side Effects of Ziconotide Use

Ziconotide does have some drawbacks. At the moment, it must be injected into the cerebrospinal fluid in the spinal cord in order to work because it can't cross the blood-brain barrier. Researchers are trying to find a way to overcome this barrier. The current means of injection into a patient is known as an intrathecal injection. It's generally performed via an infusion pump and a catheter, which must be implanted. Although the implantation might sound unpleasant, it may be very worthwhile for someone who is experiencing chronic and life-altering pain that can't be relieved by other methods.

A major advantage of injecting the drug directly into the nervous system is that the minimum amount required to relieve pain can be used. This is important because ziconotide sometimes produces significant side effects. One possible side effect of the medication is a mood change, including depression. Other possible effects are confusion, memory impairment, and hallucinations. The incidence of problems increases as dose increases.

A patient taking ziconotide must be closely monitored. The patient and people close to them should note any problems that develop. Fortunately, ziconotide use can reportedly be stopped abruptly without the patient experiencing withdrawal symptoms, allowing the side effects to disappear. It would be wonderful if researchers could discover how to block the unwanted effects of the medication.

Insulin in Cone Snail Venom

Another exciting discovery about the venom of one cone snail—Conus geographus—is that it contains a type of insulin, the hormone that diabetics lack. In addition, this insulin can bind to the human insulin receptor on the membrane of cells. New research has shown that the venom from some other cone snail species also contains insulin.

In humans, insulin stimulates the transfer of glucose (a type of sugar) out of the blood and into the cells, which use it to produce energy. As a result, the blood sugar level is lowered.

Cone snail insulin is fast acting. Within minutes of receiving the insulin injection from the snail, the prey develops very low blood sugar, experiences hypoglycemic shock, and becomes sedated. This condition makes it easy for the snail to catch the prey.

The snail insulin is not identical to the human type, but it's similar enough that its discovery has excited scientists. By studying the animal's insulin, they may be able to develop a better form of insulin for humans.

Other Possibly Helpful Chemicals in the Venom

Conantokins are a family of conopeptides found in cone snail venom. The best known member of the family is conantokin-G from the geography cone snail. The chemicals are sometimes called "sleeper peptides" because when they are injected into the brain of young mice they trigger sleep.

Researchers who are studying conantokins have discovered that they can block seizures in mice. The peptides work by a mechanism that may be helpful for humans with epilepsy, though results in mice don't always apply to humans. Nevertheless, the ability of the peptides to block specific chemical receptors in the nervous system may have benefits in epilepsy and perhaps in other disorders.

As is the case with some other cone snail chemicals, researchers have produced synthetic molecules based on the natural ones in order to improve the properties of conantokins for medical use. The chemicals are still being explored by researchers and are not yet available as medications. They could be very helpful in the future, however.

Scientists are using these neurotoxins, some powerful enough to kill people, as the basis for research into the development of life-saving drugs for medical conditions including intense chronic pain, epilepsy, asthma and multiple sclerosis.

— University of York

Population Status of Cone Snails

Unfortunately, some cone snail populations are in trouble. The snails are dying due to coastal development, ocean pollution, destructive fishing methods, and climate change. In addition, they are collected and killed for their beautiful shells, which are popular as decorations. Some shells are sold for thousands of dollars.

Researchers at the University of York in the United Kingdom have completed a population assessment for all of the 632 known cone snail species. The International Union for the Conservation of Nature (IUCN) assigns organisms to a "Red List" category according to their population status with respect to extinction. As a result of the cone snail survey, 67 species have been placed in the endangered, vulnerable, or near threatened categories in the Red List. The loss of the snails and their neurotoxins could be very unfortunate for humans.

Important Animals

It's sad when any species is threatened with extinction, but in this case the situation could hurt humans, too. What is especially worrying is that there are almost no conservation efforts for cone snails. The studies of the complex venoms of cone snails are slowly yielding wonderful possibilities for new medications. It would be very sad to lose the chance of improving treatment for pain and perhaps of discovering new treatments for diseases.

References

  • Cone snail facts from the Aquarium of the Pacific
  • First utrastructural study of the formation of the hypodermic radula teeth of Conus (abstract only) from ResearchGate
  • Snail venom painkiller from NPR (National Public Radio)
  • Information about ziconotide from the FDA (Food and Drug Administration)
  • Cone snail venom and insulin from the NIH (National institutes of Health)
  • Marine snail venom could improve insulin for diabetic patients from the University of Utah
  • Cone snails may help us to create better medicines from the phys.org news service
  • University of York cone snail survey

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2014 Linda Crampton

Comments

Linda Crampton (author) from British Columbia, Canada on February 16, 2018:

I'm glad the medication has helped you.

Prialt on February 16, 2018:

I have been on Prialt for years! I am grateful for those little snails and their venom.

Linda Crampton (author) from British Columbia, Canada on December 08, 2017:

Thank you, resseo.

resseo on December 08, 2017:

nice

Linda Crampton (author) from British Columbia, Canada on January 18, 2016:

Thank you for the congratulations and the kind comment, Flourish!

FlourishAnyway from USA on January 18, 2016:

Congratulations, Linda! Such a well done hub, as all of yours are.

Linda Crampton (author) from British Columbia, Canada on January 18, 2016:

Thank you, Mel. I appreciate your congratulations and comment very much.

Mel Carriere from San Diego California on January 18, 2016:

Congratulations on your hub of the day, Linda, for January 18th, 2016. I never knew that these pretty little snails that wash up on the beach contained something so deadly but also potentially beneficial to mankind. Great hub!

Linda Crampton (author) from British Columbia, Canada on January 18, 2016:

Thanks for the comment and the congratulations, Kristen!

Kristen Howe from Northeast Ohio on January 18, 2016:

Alicia, congrats on HOTD! This was another fascinating hub from you. I've learned a bunch on cone snails and its venom. I've never even heard of them either. Thanks for sharing.

Linda Crampton (author) from British Columbia, Canada on January 12, 2014:

Thank you, Martie. I appreciate your comment and your kind support very much!

Martie Coetser from South Africa on January 12, 2014:

The information in this hub is totally amazing and very interesting. As always I have learned a lot in your corner. Thank you, Alicia :)

Linda Crampton (author) from British Columbia, Canada on January 11, 2014:

I suspect that I know what type of snail you're talking about, Dianna, since I've written a hub about it! Not all snails are venomous, but the cone snail certainly is. I think that it's an interesting animal, though. Thank you very much for the comment.

Dianna Mendez on January 11, 2014:

I was a little taken by a huge snail I found on our garage door awhile back. I found out we are supposed to report them because they are a threat to the eco-structure here in Florida. I would not want to be stung by one! A wonderful article, as always!

Linda Crampton (author) from British Columbia, Canada on January 10, 2014:

Thank you for the comment, WriterJanis. I agree - the shells are beautiful!

Janis from California on January 10, 2014:

I had no clue about this. Thanks for the education. The shells are so beautiful.

Linda Crampton (author) from British Columbia, Canada on January 10, 2014:

This sounds like an excellent idea, Deb! We certainly need to conserve cone snails in some way. Thanks for the comment.

Deb Hirt from Stillwater, OK on January 10, 2014:

Sounds like we'd best make some conservation efforts here, so that more research ca occur on the conopeptides and other beneficial aspects. Why not snail farms?

Linda Crampton (author) from British Columbia, Canada on January 09, 2014:

Thanks for the comment, Crafty. I appreciate it!

CraftytotheCore on January 09, 2014:

This is fascinating. I never knew snails could sting at all. Well-researched. I love the photos.

Linda Crampton (author) from British Columbia, Canada on January 08, 2014:

Thank you for the visit and the comment, DDE. The cone snail is an interesting animal to write about!

Devika Primić from Dubrovnik, Croatia on January 08, 2014:

Cone Snail Venom - Medical Uses and Potential Benefits is a very interesting hub. An informative, useful and a definitely a learning lesson.

Linda Crampton (author) from British Columbia, Canada on January 07, 2014:

Thank you very much for the vote and the share, Carolyn. Nature is definitely amazing! I love the appearance of the shells, too - they're beautiful.

Carolyn Emerick on January 07, 2014:

Nature is amazing. How ironic that venom would have medicinal uses! I especially loved the images of those gorgeous shells. Found myself singing "Under the Sea" as I read along :-) Upvoted and shared

Linda Crampton (author) from British Columbia, Canada on January 07, 2014:

Thank you for the visit and the lovely comment, Nell. Cone snails are certainly amazing animals!

Nell Rose from England on January 07, 2014:

That was amazing! who would have thought that these little things could be so helpful to medical science? and that pain killer, now called Prialt! unbelievable! What a great hub Alicia, and fascinating too, thanks!

Linda Crampton (author) from British Columbia, Canada on January 07, 2014:

Thank you very much, Jodah. I hope that cone snails are protected, too. There is so much to learn about the composition of their venom and its possible uses!

John Hansen from Queensland Australia on January 07, 2014:

Wow Alicia, what an amazing hub. I learned so much about the cone shell. I hope they find a way of protecting them as the research into their toxin seems to be having wonderful medicinal results in regard to pain relief, the treatment of epilepsy etc. Voted up.

Linda Crampton (author) from British Columbia, Canada on January 07, 2014:

Hi, Writer Fox. Yes, I'm sure we're going to hear a lot more about the medical uses of cone snails in the near future. Thanks for the comment. I appreciate the vote, too!

Linda Crampton (author) from British Columbia, Canada on January 07, 2014:

Hi, Bill. Thank you very much for the comment, the vote and the share! It's interesting that a snail that is so attractive can be both dangerous and useful.

Writer Fox from the wadi near the little river on January 07, 2014:

This is amazing information. Too bad this venom isn't available on Amazon yet (just kidding). Some sharp entrepreneur will take up the call and produce these snails commercially. Enjoyed and voted up.

Bill De Giulio from Massachusetts on January 07, 2014:

Hi Linda, how fascinating. I've seen their shells but never knew they were called the Cone Snails. I had no ideas they were venomous? Or than their venom had medical uses. Thanks for the education. Voted up, shared,etc...

Linda Crampton (author) from British Columbia, Canada on January 07, 2014:

Thank you, Eddy. I appreciate your visit.

Eiddwen from Wales on January 07, 2014:

How interesting Alicia and thanks for sharing.

Eddy.

Linda Crampton (author) from British Columbia, Canada on January 06, 2014:

Thank you very much for the kind comment, Faith. I agree with you - I think we probably have only touched the surface with respect to the health benefits that other creatures can provide. Thanks for the votes and the share. Blessings to you, too, Faith.

Faith Reaper from southern USA on January 06, 2014:

I always look forward to what you will teach me with your fascinating hubs, and here is another one where I learned a lot. It is sad about possible distinction when it is so helpful to man! That first photo I thought was part of a snake buried because of the pattern on the snail. They are so very beautiful and I have never heard of them before. I believe I have seen them possibly. I sure hope there is a movement to prevent such distinction from happening. We have probably not even touched the surface of all the possibilities as far as health and what every little creature can provide.

It is great to learn something new and we can always count on you.

Up and more and sharing

Blessings, Faith Reaper

Linda Crampton (author) from British Columbia, Canada on January 06, 2014:

Thank you very much, b. Malin! It's great to hear from you again. I appreciate your comment and votes.

b. Malin on January 06, 2014:

I've MISSED your Amazing Hubs Alicia. This one was Scary and of course so Educational...who knew that such a Beautiful looking Snail could be so deadly and yet helpful in our Medical Field. I Enjoyed looking at the Videos as well. Voted UP and Interesting as well as Useful.

Linda Crampton (author) from British Columbia, Canada on January 05, 2014:

Hi, Cynthia. Yes, it is fascinating that dangerous venoms can also have medicinal uses. There is so much to learn from nature! Thanks for the comment.

Linda Crampton (author) from British Columbia, Canada on January 05, 2014:

Thanks for the comment, Bill. I appreciate your visits so soon after I publish a hub very much!

CMHypno from Other Side of the Sun on January 05, 2014:

Another interesting hub Alicia. Its fascinating how we are discovering medicinal purposes for many venoms. Also how things can be so beautiful and yet so deadly.

Bill Holland from Olympia, WA on January 05, 2014:

I learn the most interesting information from you. Well done once again my friend. I am now armed for my next game of trivia. :)