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Blue Poison Dart Frog
Transcript of Blue Poison Dart Frog
Phylum: Chordata Subphylum: Vertebrata
Class: Amphibia Order: Anura Family: Dendrobatidae Genus: Dendrobates Species: azureus Molecular formula: C31H42N2O6 The toxin is released through colourless or milky secretions from glands located on the back and behind the ears of the frogs. When one of these frogs is agitated, feels threatened or is in pain, the toxin is reflexively released through several canals to their skin. When a predator picks the frog up in its mouth it will at least experience a foul taste and probably numbness and burning as well. (Dendrobates azureus) Blue Poison Dart Frog Poison dart frogs live in the rainforests of Central and South America and on a few Hawaiian islands. There is currently no treatment of batrachotoxin poisoning. Scientists have yet to discover an antidote to the poison. There is a chance of treatment though in the treatments for one of the poisons that act in a similar way.
While it is not an antidote, the membrane depolarization can be prevented or reversed by either tetrodotoxin (from puffer fish), which is a noncompetitive inhibitor, or saxitoxin. Scientists are intrigued by the complex molecules batrachotoxin. They are extremely powerful nitrogen compounds that are a neurotoxin that interferes with the transmission of nerve impulses. The toxin in the blue poison dart frog is batrachotoxin (BTX). BTX is highly toxic with a LD50 od 0.002-0.007 mg/kg. The lethal dose for a 150 pound person would be about 100 micrograms, or the weight of two grains of table salt. The poison in the blue poisonous dart frog directly effects the nervous system. Batrachotoxin binds to and irreversibly opens the sodium channels of nerve cells. The neuron is no longer capable of sending messages and this results in paralysis.
BTX does this by increasing the permeability of the cell membrane to sodium ions. The increase of sodium depolarizes the cell membrane. The sodium channels become persistently active at the resting membrane potential. Batrachotoxin kills by permanently blocking nerve signal transmission to the muscles. The frogs' mating behavior is similar to that of most frogs. The males are quiet callers from a position in the leaves or on a rock. Females are attracted to the call and draw the male’s attention by stroking his snout. The female follows the male back to a hidden spot to lay a small clutch of 2-6 eggs that are tended by the male. Once the eggs are hatched in about 14-18 days, the blue poison dart frogs carry their tadpoles on their backs to a stream so they can develop. Once the male and female frogs have gotten the tadpoles to the stream, the tadpoles are on their own to grow for 6 more weeks until they reach adulthood Blue poison dart frogs live anywhere from 3-15 years in the wild. Their defensive weapon is their skin and the glands that secrete the toxin. The skin has little pores throughout it that let the toxin ooze out if it. The glands are surrounded by a discontinuous layer of smooth muscle cells. Within the glands are the secretory cells. Multiple flattened nuclei lie at the periphery of the gland. Most of the gland is filled with membrane-bound granules surrounded by amorphous cytoplasm. Scientists extract the toxins from the skin of the blue poison dart frog to make pain killers. One such painkiller, called Epibatidine, is 200 times as potent as Morphine. Chemicals in the poison are also showing promise as muscle relaxants, heart stimulants and appetite suppressants. The blue poison dart frog is easily recognized by its blue color, which is generally darker on the limbs and belly and overlaid with black spots or patches, especially on the head and back. They're a bright blue to warn predators that they are poisonous. Adults are about 2 inches long and weigh about 0.3 ounces. Blue poison dart frogs are active during the day and can be found hiding among boulders and debris near streams; however, they lack toe webbing and are poor swimmers, so they are never found in the water by Gabbi Radford Blue poison dart frogs are toxic because of what they eat. The ants that provide their toxicity get their chemicals to make the poison from the plants that they eat. Blue poison dart frogs would be more or less poisons as the population of the ants and the plants the ants feed on increase and decrease. http://www.rosamondgiffordzoo.org/assets/uploads/animals/pdf/BluePoisonDartFrog.pdf
You Tube video filmed at the Smithsonian National Zoo in Washington, D.C.
www.youtube.com/watch?v=kStbqxz7oec Sites Used