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"Toxin Blockin'" -- The Discovery Files

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Don't let their appearance fool you: Thimble-sized, dappled in cheerful colors and squishy, poison frogs in fact harbor some of the most potent neurotoxins we know. With new research, scientists are a step closer to resolving a related head-scratcher--how do these frogs keep from poisoning themselves?

Credit: NSF/Karson Productions

Audio Transcript:

Choose your poison

I'm Bob Karson with the Discovery Files, from the National Science Foundation.

The Phantasmal Poison Frog. (Sound effect: concert cheers) Great band name and (Sound effect: jungle swamp sounds) a tiny brightly colored amphibian found only in Ecuador. So, squishy and cute, it's hard to believe that it's packin' one of the most lethally potent neurotoxins known. Epibatidine (ep-eh-bat-ih-dine) -- a deadly defense against predators, that causes hypertension, seizures, even death.

A research team led by the University of Texas at Austin has answered the question, "with all this poison coursing through its body, how come the frog doesn't poison itself?" (Sound effect: cartoon frog 'croaks')

Turns out it's due to some lucky genetic mutations that have to do with receptors on the outside of cells. Almost like a lock, (Sound effect: lock) they stay shut (Sound effect: door close) unless a key comes along that fits. The reason epibatidine is so insidious is it can spoof as a master key. (Sound effect: baseball crowd) Here's where evolution throws a curveball (Sound effect: loopy slide whistle) for the frog team. One mutation in the frog's genes blocks the poison's master key and another allows healthy molecules' keys to still work. Hence, our frogger is protected from its own protection.

The same receptors in humans are involved with pain and nicotine addiction. Understanding the way the lock changed suggests possible new ways to develop non-addictive drugs to block pain or help smokers kick the habit.

(Sound effect: mouth harp) Thanks to some toxic mutant ninja frogs.

"The discovery files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.

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