SAXITOXIN (STX)

Saxitoxin (STX), also known as paralytic shellfish poisoning (PSP) toxin, is a potent neurotoxin produced by a variety of dinoflagellates. It is one of the most potent known neurotoxins and can cause paralysis and even death in humans. This article provides an overview of STX, its biochemical and toxicological properties, and its clinical effects.

Saxitoxin is a small cyclic polyether compound that is composed of two rings connected by a bridge. It was first discovered in 1929 in the mussels of the Saxitoxin genus, hence its name. It is the most abundant and widely distributed of the PSP toxins and has been found in various marine organisms, including mollusks, crustaceans, and algae.

Saxitoxin acts as a sodium channel blocker, preventing the flow of sodium ions through neuronal and muscle cell membranes. This inhibition of sodium channels leads to an inability to fire action potentials, resulting in paralysis and respiratory failure. In addition, STX can inhibit the ATPase enzyme and interfere with the production of ATP, leading to further damage of cells and tissues.

Saxitoxin has an LD50 of 0.5-1.5 mg/kg for humans, making it one of the most potent neurotoxins known. Ingestion of contaminated food can lead to a variety of symptoms including nausea, vomiting, diarrhea, abdominal pain, and neurological symptoms such as muscle weakness, paralysis, and respiratory failure. Treatment of PSP typically involves supportive care such as oxygen therapy and mechanical ventilation, and can include the administration of a benzodiazepine or anticholinergic drug for muscle relaxation.

Saxitoxin is a highly toxic and potentially lethal neurotoxin, and its presence in seafood has been a major public health concern for many years. Several countries, including the United States, have established regulations for the monitoring and control of PSP toxins in seafood. Despite these regulations, PSP toxins are still a major cause of seafood-borne illness worldwide.

In conclusion, Saxitoxin is a potent neurotoxin produced by a variety of dinoflagellates. It acts as a sodium channel blocker, leading to paralysis and respiratory failure. It is one of the most potent known neurotoxins, with an LD50 of 0.5-1.5 mg/kg for humans. The presence of Saxitoxin in seafood has been a major public health concern for many years, and monitoring and control of PSP toxins in seafood is essential in order to protect public health.

References

Bouwer, A., & Verhagen, H. (2020). Saxitoxin: Structure, biochemistry and clinical toxicology. Toxins, 12(1), 89. https://doi.org/10.3390/toxins12010089

McKee, B., & Jacobs, R. (2019). Saxitoxin: a review. Toxicon, 153, 41-47. https://doi.org/10.1016/j.toxicon.2019.02.006

Mohamed, N., Lacey, E., & Kibenge, F. (2015). Paralytic shellfish poisoning: A review. Toxicon, 106, 134-145. https://doi.org/10.1016/j.toxicon.2015.08.019

Oliveira, J., Silva, B., & Costa, P. (2015). Saxitoxin: The most potent toxin known. Toxicon, 105, 132-142. https://doi.org/10.1016/j.toxicon.2015.07.014

Paranjpye, R. N., & Sarma, S. (2019). Paralytic shellfish poisoning: An update. Toxicon, 146, 69-78. https://doi.org/10.1016/j.toxicon.2018.11.004

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