Neurotoxins shellfish poisoning

Rapid-acting paralytic neurotoxins that blocks transient sodium channels and inhibits depolarization of nerve cells. They are some of the causative agents of paralytic shellfish poisoning (PSP). They are obtained from dinoflagellates (Gonyaulax spp., Alexandrium spp.) and cyanobacteria (Anabaena circinalis). 

The neurotoxins may be transmitted to man through bioaccumulation in an intermediate marine host. Toxic bivalves result from the filter-feeding of jP. brevis cells during red tides, and if consumed result in neurotoxic shellfish poisoning, or NSP. Human oral intoxication is rarely fatal. 

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. 

The red alga Digenea simplex has been used for the treatment of roundworm disease for centuries. Its active principle is kainic acid. The related domoic acid is a constituent of another red alga, Chondria armata, used for the same purpose. These compounds, known as kainoids, are potent neurotoxins and excitatory amino acids. Kainoids are important tools in neurophysiological research. Domoic acids are also produced by diatoms and were responsible for the shellfish poisonings known as amnesic shellfish poisonings that occurred in Canada in 1987. 

Saxitoxin (32) is listed in Schedule 1 of the CWC. It is a polar, cationic, relatively low molecular mass toxin and is one of 18 structurally related neurotoxins collectively known as paralytic shellfish poisoning (PSP) toxins. Analogues are formed by addition of sulfate, A-sulfo and A-hydroxyl groups, and by decarbamylation. They block neuronal sodium channels, and thereby neurotransmission, death resulting from respiratory paralysis. Saxitoxin is produced by dinoflagellate species (and by some freshwater cyanobacteria), and accumulates in shellfish. The cationic nature of saxitoxin makes capillary electrophoresis combined with... 

Saxitoxin (STX) is a potent neurotoxin that can cause paralytic shellfish poisoning (PSP). Produced by certain strains of dinoflagellates, saxitoxin leads to the contamination of commercial shellfish and cause severe outbreaks of seafood poisoning. The public health problems caused by these outbreaks have led to significant interest in the development of analytical methods for the analysis of saxitoxin in environmental and biological samples. Saxitoxin is also one of a series of several closely related... 

IPC is also effective for pharmacology related to brain disease. It was used to analyze picolinic acid and related compounds [90], neurotoxins associated with paralytic shellfish poisoning [91], a drug candidate for treating Alzheimer s disease [92], and nicergoline, clinically used for improving brain metabolism [93]. Quaternary ammonium anticholinergics were determined in whole blood and the matrix effect was taken into account [94]. 

Chemical Abstracts Service Registry Number CAS 14277-97-5. Domoic acid, a glutamic acid analog that is resistant to temperature extremes, is an excitatory neurotoxin produced by a diatom and concentrated in shellfish. Ingestion leads to amnesic shellfish poisoning, which can also include seizures. Its relevance to use in warfare and terrorism, apart from its being unfamiliar to most disaster-response personnel, is that it is also easily absorbed by inhalation and across mucous membranes. No specific antitoxin is available, and treatment is supportive. 

Saxitoxin, the best known example of this group, is a potent neurotoxin found in shellfish such as mussels, clams, and scallops. Saxitoxin is a sodium channel-blocking agent and is more toxic by inhalation than by other routes of exposure. Unlike oral intoxication with saxitoxin (paralytic shellfish poisoning), which has a relatively slow onset, inhala-tional intoxication with saxitoxin can be lethal in a few minutes. Saxitoxin could be used against our troops as an antipersonnel weapon, but because it cannot currently be chemically synthesized efficiently, or produced easily in large quantities from natural sources, it is unlikely to be seen as an area aerosol weapon on the battlefield. 

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