Fwd: Frogs' poisons being studied at Aquarium of the Americas

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Research for new meds... Lee

Saturday Special No Prince Charming Frogs' poisons being studied at Aquarium of the Americas By JOE GYAN JR. New Orleans bureau Advocate staff photo by Alan HannonIan Hiler, the assistant director of husbandry and animal exhibit designer for the Aquarium of the Americas, holds one of the poison-dart frogs being studied in New Orleans. NEW ORLEANS -- In an inconspicuous warehouse on the outskirts of the French Quarter, hundreds of endangered and potentially deadly amphibians are in varying stages of development at an Aquarium of the Americas off-site breeding facility.They come in a rainbow of colors -- yellow, red, green, orange, blue, black, or any combination -- and grow no larger than two inches long. But the toxins secreted by some of these tiny "poison-dart frogs" can kill animals the size of monkeys, and in some cases humans.At the same time, medical research continues to examine uses of the toxins as an anesthetic and to treat pain."A lot of these animals have never been studied. They could have all kinds of cures," said Ian Hiler, assistant director of husbandry and animal exhibit designer for the Aquarium of the Americas in New Orleans.Hiler has been studying poison-dart frogs for 19 years, traveling to Ecuador, Peru, Costa Rica and Panama, to name a few locations. The frogs live in the rain forest and cloud forest of Central and South America from sea level to 8,000 feet in elevation.The aquarium, located along the Mississippi River at the foot of Canal Street, is the country's leading breeder of poison-dart frogs and the world's second-largest breeder.Hiler and his staff raised more than 1,000 poison-dart frogs last year at the aquarium's off-site warehouse, which is closed to the public.Poison-dart frogs from the New Orleans aquarium's collection can be found all over North America in aquariums and zoos, including the National Aquarium in Baltimore and the Shedd Aquarium in Chicago. Some are on display at the Aquarium of the Americas' Amazon Rainforest exhibit and at the Audubon Zoo's reptile house.The number of known species of poison dart frogs now exceeds 180, Hiler said, but three of the species give the frogs their ominous name. Two of those three species, including the deadliest and bright yellow Phyllobates terribilis, nicknamed "terrible dart frog," are bred at the aquarium's warehouse."It takes two milligrams (about 1/10th of a raindrop) to kill a human," Hiler said of the terrible dart frog's poison.However, it is rare that humans are killed by the dart frog.The dart frogs bright colors warns predators that it is poisonous.Some native South Americans, namely the Choc-- Indians, use the poison from the three most toxic frogs to make poisonous darts for hunting. They've been doing this for 5,000 years, Hiler said.They capture the frogs by using a leaf to pick them up so the poison doesn't get on their hands. They rub the tip of the dart in the poisonous mucous on the frog's skin and the dart is ready for the blowgun. The mucous contains a deadly alkaloid similar to curare, a black, substance prepared from the juices of certain South American plants and used for poisoning arrows.After killing an animal, such as a howler monkey, the native licks its flesh very briefly to find the part of the carcass affected by the toxin and cut it away. Since guns arrived in the rain forest, the crafting of dart guns has become a dying art among the Choc-- people of Colombia.Like the blowgun, Hiler said, the poison dart frogs themselves are endangered because of the rapid destruction of their tropical rain forest habitat in lower Central America and northern South America. The deforestation also means medical researchers are frantically trying to study all the species before many are driven to extinction.Alkaloid toxins are of great interest to pharmaceutical companies as a possible means of pain control in heart disease and as a localized anesthetic. Hiler said all the dart frog species produce multiple types of alkaloids often unique to the species."Some species have as many as 22 (toxins) on their backs," he said.A deadly poison from the skin of an Ecuadorian frog called Epibpedobates tricolor, which is bred at the New Orleans aquarium warehouse, provided the decisive clue for the discovery of a powerful new painkiller.Researchers say the painkiller may have all the benefits of morphine without the damaging side effects, according to the National Institutes of Health. Morphine is the main drug used for treatment of intense and unrelenting pain, such as from cancer or injury.NIH said the frog exudes epibatidine, a chemical with analgesic qualities. The substance, 200 times as powerful as morphine, shows great medicinal promise, especially for patients who don't respond to painkillers derived from opium poppies, NIH said.Poison dart frogs caught in the wild gradually become less poisonous, Hiler said, and captive offspring are nontoxic. The change may be because of diet, he said. The frog's natural menu -- mostly insects such as tropical ants and termites which feed on toxic tropical plants -- cannot be duplicated in a terrarium.