Poisons batrachotoxin

Frog poison. Batrachotoxin (BTX) is a steroidal alkaloid from the skin of Phyllobates terribilis, a poisonous Colombian frog (source of the poison used on blowgun darts). In the presence of BTX, sodium channels in an excised patch stay persistently open when the membrane is depolarized. They close when the membrane is repolarized. Which transition is blocked by BTX ... 

FIGURE 10.5 Batrachotoxin from dart-poison frogs. 

The active principle of dart frog poisons is alkaloids. The study of the den-drobatid poisons led to the discovery of over 200 new alkaloids, including batrachotoxins Pig. 10.5), pumiliotoxins, histrionicotoxins, gephyrotoxins, and decahydroquinolines (Daly et al., 1994). The most common compounds have the basic structure of piperidine and include histrionotoxin. In Phyllobates, the synthesis of other alkaloids is suppressed in favor of batrachotoxins. These are... 

Several major types of animals that produce poisonous substances have been considered so far in this chapter. With the exception of birds, all classes of the animal kingdom contain members that produce toxic substances. It has now been demonstrated that there are even birds that are toxic. It is believed that such birds do not produce toxins but accumulate toxic alkaloids, including andromedotoxin, batrachotoxins, and cantheridin, from their diets and deposit these poisonous materials in their skin and feathers.19 Toxic animals not covered so far in this chapter are summarized here. 

Batrachotoxin A (III), just one of many steroidal alkaloids, is one of the most lethal substances known (LD50 = 2/xg/kg subcutaneously in mice). It is found in the skin secretions of the brightly colored tropical frog Phyllobates aurotaenia and is used by Colombian Indians to prepare poison darts. 

Batrachotoxin, not unexpectedly in view of its use as a dart poison by South American Indians, is an extremely toxic substance. The LDjq on subcutaneous injection in mice is about 40 ng. Homobatrachotoxin is only slightly less toxic, while batrachotoxinin A is 500-fold less toxic. The nature of the ester function at the 20a position is of critical importance to toxicity. Thus, the 20a-benzoate of batrachotoxinin A is fully as toxic as batrachotoxin, whereas the 20a-4-bromobenzoate has very low toxicity. For a summary of the toxicides of natural and synthetic batrachotoxins, see Ref. 5. 

Batrachotoxin (459), the steroidal alkaloid from the poison arrow frog Phyllo-bates aurotaenia, continues to engage the attention of chemists and pharmacologists. This substance exerts novel, selective effects on electrogenic membranes. In many cases this activity can be explained in terms of an irreversible increase in permeability to sodium ions. The subsequent reactions promoted by (459) can be blocked reversibly by tetrodotoxin. ... 

Synonyms Fhyllobates toxin Pitohui toxin Ifrita toxin poison dart frog toxin Chemical/Pharmaceutical/Other Class Steroidal alkaloid neurotoxin Chemical Formulas o Batrachotoxin C31H42N2O6 o Homobatrachotoxin C32H44N2O6 o Batrachotoxinin-A C24H35NO5... 

Daly JW, Myers CW, Warnick JE, and Albuquerque EX (1980) Eevels of batrachotoxin and lack of sensitivity to its action in poison-dart frogs Phyllobates). Science 208 1383-1385. 

Brown GB (1988) Batrachotoxin a window on the allosteric nature of the voltage-sensitive sodium channel. Int Rev Neurobiol 29 77-116 Brunton L, Cash T (1883) Influence of heat and cold upon muscles poisoned by veratria. J Physiol (Lond) 4 1-17... 

Crosby DG (1971) Minor insecticides of plant origin. In Jacobson MJ, Crosby DG (eds) Naturally occurring insecticides. Dekker, New York, pp 177-239 Cukierman S (1991) Inactivation modifiers of Na currents and the gating of rat brain Na channels in planar lipid membranes. Pfliigers Arch 419 514-521 Daly JW, Myers CW, Warnick JE, Albuquerque EX (1980) Levels of batrachotoxin and lack of sensitivity to its action in poison-dart frogs (Phyllobates). Science 208 1383-1385... 

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