The phantasmal poison frog, Epipedobates anthonyi, is the original source of epibatidine, discovered by John Daly in 1974. In fact, epibatidine is named for frogs of this genus. Epibatidine has not been found in any animal outside of Ecuador, and its ultimate source, proposed to be an arthropod, remains unknown. This frog was captured at a banana plantation in the Azuay province in southern Ecuador in August 2017.REBECCA TARVIN
Poison frogs become poisonous by isolating chemicals from their food and storing them in their skin. One such compound, epibatidine, is a stronger painkiller than morphine, but has not been tested in humans because even low doses are deadly to rodents. But for the frogs themselves, this powerful neurotoxin is totally impotent.
According to a study published today (September 21) in Science, several groups of epibatidine-bearing frogs have independently evolved amino acid changes in the toxin’s target, the nicotinic acetylecholine receptor. These modifications allow the amphibians to escape self-toxicity, yet preserve the receptor’s ability to bind the neurotransmitter acetylcholine.
The authors “show DNA sequence changes [and] amino acid sequence changes that have happened multiple times in multiple lineages of frogs,” says Joel McGlothin, an evolutionary ...
