Saxitoxtoxins
Saxitoxins are a group of potent neurotoxic alkaloids produced by certain species of cyanobacteria and dinoflagellates. These toxins are known for their role in causing paralytic shellfish poisoning (PSP) in humans and other animals that consume contaminated seafood. The primary mechanism of action for saxitoxins involves blocking voltage-gated sodium channels in nerve and muscle cells. By inhibiting the influx of sodium ions, saxitoxins prevent the generation and propagation of action potentials, leading to paralysis. Symptoms of PSP can range from mild numbness and tingling to severe respiratory paralysis and death, depending on the dose ingested. Saxitoxins are not degraded by cooking, making contaminated shellfish a persistent risk. They are water-soluble and can accumulate in filter-feeding organisms like mussels, clams, and scallops. Monitoring programs are in place in many coastal regions to test shellfish for saxitoxin levels and issue warnings when dangerous concentrations are detected. Research continues into the synthesis, ecological roles, and potential medical applications of saxitoxins, though their toxicity remains a significant concern for public health.