Neurotoxin, frog

Neurotoxin, frog, 86 Nitriles, 146-150 intramolecular, 149-150 Nitrosobenzene, cycloaddition, 72-78 Nitrosyl cyanide, 87... 

Very rapid-acting paralytic neurotoxin that binds to sodium channels of nerve and muscle cells depolarizing neurons by increasing the sodium channel permeability. It is obtained from South American poison-dart frogs (Phyllobates aurotaenia, Phyllobates terribilis). It is insoluble in water but soluble in hydrocarbons and other nonpolar solvents. The dried toxin can remain active for at least a year. However, it is relatively nonpersistent in the environment. 

Rapid-acting neurotoxin that inhibits sodium-ion channels in neural and muscular tissue. It does not affect the neuromuscular junction. It is colorless crystals or a white powder that is obtained from puffer fish (Arothron sp.), frogs, newts, dinoflagellates (Takifugu poecilonotus), and bacteria (Pseudoalteromonas tetraodonis). It is heat stable but darkens on heating above... 

The neurotoxins isolated from Aph. flos-aquae were shown to have similar chemical and biological properties to paralytic shellfish poisons (PSP) (25,29,38) Sawyer et al. in 1968 (25) were the first to demonstrate that the crude preparation of aphantoxins behave like saxitoxin, the major paralytic shellfish poison. They showed that the toxins had no effect on the resting membrane potential of frog sartorius muscle blocked action potential on de-sheathed frog sciatic nerve and also abolished spontaneous contractions in frog heart. Sasner et al. (1981) (29) using the lab cultured strain reported similar results. 

Hanna PA, Jankovic J, Vincent A (1999) Comparison of mouse bioassay and immunoprecipitation assay for botulinum toxin antibodies. J Neurol Neurosurg Psychiatry 66 612-16 Hanson MA, Stevens RC (2000) Cocrystal structure of synaptobrevin-II bound to botulinum neurotoxin type B at 2.0 A resolution. Nat Struct Biol 7 687-92 Harlow ML, Ress D, Stoschek A, Marshall RM, McMahan UJ (2001) The architecture of active zone material at the frog s neuromuscular junction. Nature 409 479-84 Harris JB (1997) Toxic phospholipases in snake venom an introductory review. Symp. zool. Soc. Lond. 70 235-50... 

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... 

In New Guinea, traditional hunters are aware that Pitohui and Ifrita birds carry neurotoxins. Local names for these birds often reflect the fact that they are bitter or contain burning chemicals. Toxins in these birds are more diffuse than in the frogs, but even a single feather, if tasted, can cause an acute burning... 

An intramolecular nitroso Diels-Alder approach to the frog neurotoxin gephyrotoxin 223AB (25) has recently been reported (Scheme 3-XIV). Cyclization of the nitroso compound derived from hydroxamic acid 23 afforded the bicyclic adduct 24 in good yield, directly establishing two of... 

Tetradotoxin is a potent neurotoxin isoiated from the ovaries and liver of many species of Tetradodontidae, especiaiiy the Japanese fugu (or puffer fish). Saxitoxin is a mussel or clam poison produced by certain marine dinoflagellates, Gonyaulax catenella or G. tamarensis, the consumption of which cause the mussels or clams to become poisonous. These poisonous shellfish were connected to a toxic red tide environmental condition on the coastal region of California in early 1970. Batrachotoxin is a cardiotoxic and neurotoxic steroid isolated originally from the poison dart frog, Phyllobates terribilis. It is a lipid soluble neurotoxin that is at least 10-fold more toxic than tetradotoxin. 

Kim, Y.H., Kim, Y.B., and Yotsu-Yamashita, M. 2003. Potent neurotoxins Tetrodotoxin, chiriqui-toxin, and zetekitoxin from Atelopus frogs in Central America. J. Toxicol-Toxin Rev. 21, 521-532. 

A synthesis of the frog neurotoxin ( )-gephyrotoxin (124) uses the intramolecular Diels-Alder reaction of an acyl nitroso-compound, generated by situ periodate oxidation of the hydroxa-mic acid (121), to form the piperidine portion (122) of the molecule. After introduction of the propyl residue, reduction and protection to (123), the synthesis was completed by hydrogenation... 

Batrachotoxin a neurotoxin from the skin of the Columbian arrow poison frog, Phyllobates. It causes... 

Histrionicotoxin, a paralyzing neurotoxin from certain poison dart frogs. 

Colombian poison dart frogs are tiny, beautiful, and deadly. They produce a poison called histrionicotoxin, which is an amine that causes paralysis. Death from histrionicotoxin results by suffocation through paralysis of the victim s respiratory muscles. (A molecular model of histrionicotoxin is shown above.) Curare, the Amazonian arrow poison that is a mixture of compounds from a woody vine, contains another paralytic neurotoxin, called cf-tubocu-rarine. Histrionicotoxin and d-tubocurarine both block the action of acetylcholine, an important neurotransmitter. Amines like these and others have fascinating roles in biological systems, as we shall see in this chapter while studying the properties, reactivity, and synthesis of amines. 

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