VPT 421: Veterinary Toxicology (2+0)

FISH POISONING

• Tetrodotoxin is a bacteria-derived organic molecule assimilated into the tissues of the pufferfish or into the modified salivary glands of the blue-ringed octopus.
• About 100 species of puffer fish use the powerful tetrodotoxin to discourage consumption by predators.

• The puffer fish is the best known neurotoxic fish.
• Tetrodotoxinis found in all organs of the fish but is highest in liver, skin, andintestine.
• Pufferfish may also have elevated levels of saxitoxin, a neurotoxin responsible for paralysis in shellfish poisoning.
• Saxitoxin is also produced by algae.
• Both saxitoxin and tetrodotoxin are heat stable and cooking does not reducetoxicity.
• Saxitoxin has a very different chemical structure to tetrodotoxin, but similar effects on transport of cellular sodium; it produces similar neurological effects, but isless toxic that tetrodotoxin.
• Tetrodotoxin causes paralysis by affecting sodium ion transport in both the central andperipheral nervous system.
• A low dose of tetrodotoxin produces tingling sensations and numbness around the mouth, fingers, and toes.
• Higher doses produce nausea, vomiting, respiratory failure, difficulty in walking,extensive paralysis, and death.