New and Improved Deadly Snail Venom

SoyChemist writes "In 2004, the FDA approved the cone snail venom ziconotide (Prialt) for the treatment of chronic pain. It is only used for severe cases because it must be injected directly into the spinal column. This month, researchers from the University of Utah have reported the discovery of a new snail venom with a completely different amino acid sequence. Because it very selectively attaches to and blocks nerve signals by binding to a particular type of acetylcholine receptor without causing any collateral damage, the newly discovered venom could also become a fantastic medical tool."

Comments

Cone snails

[BWJones]

You really should see these snails hunt and eat fish .

Some years ago, I spent a bit of time in Toto Olivera's lab (the guy who pioneered all of the conotoxin research) and it was amazing to watch these snails follow, track and eventually harpoon and eat fish in the aquarium. It turns out that the poison these snails use is a complex cocktail of peptides and small molecules that act on a variety of protein channels with implications for everything from the pain mentioned in the article to anesthesia to anti-convulsants.

Re:Cone snails

[makuabob]

You really should see these snails hunt and eat fish.

Yes, indeed! I lived in Hawaii for several years, was a SCUBA-diving shell collector and kept two aquaria--one with Textile cones (a molluscivore, i.e., eats other snails) and one with Striated cones (a piscivore). (Had to keep 'em apart, for obvious reasons.)

One Striated cone in my aquarium eventually learned that it was in a closed area. Normally, these fish-killers 'spear' their food and hold on to the barbed, radular tooth (through which the vemon is injected) until the fish is paralyzed (two or three seconds), then draw the prey into their extended, enveloping stomach. After that, they dig into the sand and digest for a couple of weeks; if they're lucky, they don't get eaten in turn by an Eagle Ray,... or one of those Textile cones mentioned above.

So, anyway, this one Striated cone quit holding onto the 'spear' once it hit the fish and, instead, would stroll around the aquarium until it found its meal! (In an embarassing faux pas, it once shot a dart through its own siphon and spent a couple of minutes trying to eat itself !)

Be glad these things aren't crawling around your garden; one shot from these could be your last! They are not too shy to defend themselves. Every year there are fatalities in the topical islands where some of the most venomous and aggressive varieties live.

Works faster than nerves conduct?

[CRCulver]

Something like 15 years ago I read a Michael Crichton novel (I suspect it was Sphere ) where a character claimed that the chemical reactions of cone snail venom "works faster than nerve conduction velocity", meaning that one is dead before one even feels the sting. Is there truth to this, or is it totally false?

Re:Works faster than nerves conduct?

[iamdrscience]

Everything Michael Crichton writes is absolutely true. Don't believe me? Come over and I'll let you go for a ride on my pet dinosaurs.

Re:Works faster than nerves conduct?

[fishthegeek]

That was Jurassic Park.

[about the poison on the darts in their guns]
Eddie Carr: The most powerful neurotoxin in the world. It works faster than the nerve conduction velocity, which means the animal's down before it actually feels the - P! - prick of the dart.
Dr. Ian Malcolm: Is there an antidote?
Eddie Carr: What, like if you shot yourself in the foot? Don't do that, you would be dead before you even knew you had an accident.

According to this article http://www.pubmedcentral.nih.gov/articlerender.fcg i?artid=25694 the effect of the venom is merely "near instantaneous" as opposed to the faster claim of Eddie Carr.

Re:Works faster than nerves conduct?

[Ihlosi]

Is there truth to this, or is it totally false?

There is some truth to this. In many cases, victims of these snails don't realize that they've been stung. However, this has nothing to do with the poison, but with the injury being really minor.

Re:Nature Vs Lab

[m50d]

"Of course, their insistence that ground rhino horn will bring back a man's impotent tallywhacker....the jury's still out."

No, the jury's not in any sense out. It doesn't work. And therein lies the problem with traditional medical "knowledge" - for every valid remedy there are four which are pure codswallop.

ACH Receptor blockers have a lot of potentials

[einhverfr]

as antitoxins as well.

The most famous ACH receptor blocker is atropine (a poison itself derived originally from Atropa belladonna). This particular characteristic of atropine is why it is used to treat poisoning of several classes of poisons including Cholinesterase inhibitors (which include all current forms of chemical weapon nerve agents and a number of pesticides as well), muscarine (such as from certain forms of mushroom poisoning, f. ex. aminita muscaria) and the like.

Of course anything that touches the ACH cycle in the nerve is likely to be potentially deadly...

Re:Nature Vs Lab

[It'sYerMam]

"My pharmacological background is limited, but I imagine that side effects with naturally created drugs are minimized compared to those synthesized in a lab."

I'm afraid you imagine wrong, at least in a theoretical sense. Side effects (and primary effects) are determined solely by the interaction of the chemical(s) with the human body, and there's no overarching difference between synthetic and naturally occurring chemicals - when you get down to it, it's all just a bunch of quarks and electrons. It tends to be possible to create more complex compounds naturally, however. So when we manufacture penicillin, we get some mould to secrete the basic ingredient, then substitute on different chemical groups to obtain different effects in the body - to produce a stronger, faster acting compound, with fewer or lesser side effects - hopefully. When it comes down to it though, lead compounds for drugs aren't really designed, they're discovered. Most of those compounds - like those that spawned aspirin, paracetamol, penicillin and the like - are naturally occurring. I suppose a few must have been discovered in synthetic compounds, but not many. The reason being that natural compounds, due to the way they are produced, can be much more complex. Drugs can have many chiral centres, and in classic syntheses, you'd obtain a mixture of all the different possible isomers - usually only one works. When an enzyme produces the feedstock, the compound is more likely to be a pure, or purer mixture, since the shape of the enzyme tends only to catalyse the production of one isomer. This restricts synthetic medicines to much simpler molecules until our synthetic procedures improve (which they are doing - designer molecules are becoming possible.) Even then, however, we have some way before we look at the shape of receptor sites and try and devise molecules to fit them. We are still at the stage where we notice a compound has a physiological effect, and then start looking closer.

I would like to try this.

[pair-a-noyd]

I live in constant, extreme pain 24 hours a day from a broken spine.
The break was repaired by spinal fusion and titanium hardware but I got ZERO pain relief from the surgery.
If anyone else had to live with the pain I live with, they would commit suicide before the end of the first day.

My surgeon told me to "just get over it".. I'm now at the point that I would gladly allow a doctor to severe the nerves so that I would lose all feeling from my neck down. Even if it left me paralyzed it would be worth it, just to stop hurting.
My problem is is that I can't work, don't have insurance, income, or anything else.
I don't qualify for assistance because I was self employed for too many years.

If some doctor would like to try this snail stuff out on me, I volunteer. I can't tolerate the pain anymore.