Marine biotoxin NSP (Neurotoxic Shellfish Poisoning) in bivalve molluscs (Brevetoxins-brevetoxicosis): mouse bioassay test.
The neurotoxic shellfish poisoning (NSP-neurotoxic shellfish poisoning) is a disease caused by marine biotoxins due to ingestion of contaminated bivalve molluscs with polietéricas neurotoxins methylated cyclic thermostable known as brevetoxin. These toxins are classified into two groups (types A and B) by polyether structure. The type A contains two cyclic ether ring and includes the Tx-1, Tx and Tx-7-10 toxins; Type B contains 11 etheric rings and includes the Tx-2, Tx-3, 5-Tx, Tx-6, 8-Tx and Tx-9 toxins. Of these the more potent the Tx-1, and frequently the Tx and Tx-2-3. The toxic effects on man are caused by activation of sodium channels in nerve cells, which causes uncontrolled influx of sodium ions which depolarize the membrane. In people poisoning manifested by a set of gastrointestinal and neurological symptoms (abdominal pain, ataxia, diarrhea, dizziness, myalgia, nausea, paresthesia, vomiting, chills), which are similar to those caused by poisoning ciaguatoxinas -ciguatera- Of fishes. No fatalities have been reported by this poisoning, but some people require hospitalization, and its effect has a negative impact on trade in bivalve molluscs. Mouse bioassay is the reference method. They described alternative methods (enzimoinunoensayos, functional assays receptor binding spectrometry, liquid chromatography mass), although they have higher sensitivity compared to the mouse bioassay not detect toxicity contaminated Brevetoxins molluscs, and some of these methods, such as immunoassays cross - react with metabolites nontoxic brevetoxins, or other non corresponding to brevetoxins chemicals. Also, some very potent Brevetoxins are not detected by immunoassays. In our laboratory we perform the method mouse bioassay using purified extracts of tissues of bivalve molluscs extracted with diethyl ether, and expressing the results, should be positive in MU (Mouse Units Units mouse).