Saxitoxin

Saxitoxin (STX) is a potent neurotoxin and the best-known paralytic shellfish toxin (PST). Ingestion of saxitoxin, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the human illness known as paralytic shellfish poisoning (PSP).

Structure and reactivity

Saxitoxin has a complex molecular structure that includes an unusual tricyclic arrangement of atoms. This structure is responsible for the molecule's ability to block sodium channels and thereby disrupt nerve function.

Synthesis and occurrence

Saxitoxin is produced by certain species of marine dinoflagellates and freshwater cyanobacteria. The toxin accumulates in shellfish that feed on these microscopic organisms.

Toxicity

Saxitoxin is one of the most potent natural toxins known. It acts by blocking sodium channels in nerve cells, preventing the transmission of nerve impulses and leading to paralysis and potentially death.

Treatment and prevention

There is no known antidote for saxitoxin poisoning. Treatment is supportive and includes respiratory support if necessary. Prevention involves monitoring of shellfish beds for toxic algal blooms and closure of these beds to harvesting when toxin levels are high.

See also

• Paralytic shellfish poisoning
• Dinoflagellate
• Cyanobacteria
• Neurotoxin

Saxitoxin

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  Saxitoxin neutral structure
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  Neurotoxin sodium channel binding sites
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  Saxitoxin biosynthesis