Poisons tetrodotoxin

A variety of toxins that modulate voltage-gated sodium channels have been used to probe channel function. They can be classified on the basis of five discrete binding sites (Table 1). These binding sites are commonly found on all a-subunits and are being characterized at the molecular level. The sensitivity to the puffer fish poison tetrodotoxin (TTX) has been used to subdivide voltage-gated sodium channels (Table 3). 

The functional heterogeneity of Na channels in sensory neurons was detected using the channel blocking activity of the puffer fish poison tetrodotoxin (TTX)... 

Ahasan HA, A1 Mamun A, Rasul CH, Roy PK. Puffer fish poisoning (tetrodotoxin) in Bangladesh clinical profile and role of anticholinesterase drugs. Trap Doct 35 235-236, 2005. 

A variety of toxins may produce illness after ingestion of fish or shellfish. The most common types of seafood-related toxins include ciguatera, scombroid, neurotoxic shellfish poisoning, paralytic shellfish poisoning, tetrodotoxin, and domoic acid. Shellfish-induced bacterial diarrhea is described on p 203. 

Saxitoxin (STX) is a toxin which is found in marine microorganisms. It is most likely synthesized by bacteria which live in symbiosis with dinoflagellates, a component of phytoplankton. Through the marine food chain, it can lead to poisoning of humans. The mechanism of toxicity of saxitoxin is vety similar to that of tetrodotoxin. Saxitoxin binds from the outside of the membrane to various forms of voltage-sensitive Na+channels and blocks the channel in an activation state-independent manner. 

Tetrodotoxin poisoning has been recogniz for more than two thousand years. Japanese historical records show that the consumption of certain species of pufferOsh (Tetraodon spp.) resulted in paralytic intoxication (8), This problem continues in modern times in various i ian countries, especially Japan, where pufferfish are still regarded as a delicacy. Clinical symptoms of TTX intoxication include numbness, paralysis, and in some instances death. In fact, the "zombie state described in the Voodoo religion has been attributed to TTX in potions derived from pufferOsh (9). 

Tsai, Y.H., et al., Occurrence of tetrodotoxin and paral5dic shellfish poison in the... 

Yang, C., et al.. An outbreak of tetrodotoxin poisoning following gastropod mollusc consumption. Hum. Exp. Toxicol., 14, 446, 1995. 

Hwang DF, Noguchi T. (2007) Tetrodotoxin poisoning. Adv Food Nutr Res 52 141-236. 

Pioneering studies were made to determine the structure of tetrodotoxin 1, one of the most toxic compounds among the low-molecular-weight poisons, found in the ovaries and liver of puffer fish, which is a highly esteemed delicacy in Japan. With a combination of the most versatile instrumental facilities, the complex perhydroquinazoline structure of 1 was established (65T2059) in the early 1960s. 

Over the last eight years, most of the estimated cases of world-wide poisoning in humans due to the three major kinds of seafood toxins that are found in fresh and unspoiled marine organisms, namely, paralytic shellfish poison (PSP-saxitoxins/ gonyautoxins), ciguatoxin(s), and tetrodotoxin, (13-16) were caused by ciguatera (Table I). 

Goby Poisoning. At least one species of the family Gobiidae, namely Gobius criniger, has been found to contain tetrodotoxin (89, 90). Fatalities to humans and animals have been reported in Taiwan, and this goby is known to be toxic in the Philippines and Ryukyu Islands. 

---