Tetrodotoxin

Tetrodotoxin is a potent neurotoxin that blocks voltage-gated sodium channels, preventing electrical impulses from traveling through nerves and muscles.

Voltage-gated sodium channel: A membrane protein that opens in response to voltage changes and allows sodium ions to cross cell membranes. Tetrodotoxin binds to these channels and obstructs sodium entry.
Pufferfish: A fish in the order Tetraodontiformes, several species of which accumulate tetrodotoxin in tissues. Pufferfish are the best-known animals associated with tetrodotoxin poisoning.
Neurophysiology: The study of how nervous systems function, including the electrical properties of neurons. Tetrodotoxin helps isolate sodium-channel-dependent electrical activity in experiments.
Fugu: Japanese cuisine prepared from pufferfish by specially licensed chefs. Improper preparation can leave tetrodotoxin in edible tissues.
Action potential: A rapid, temporary change in a cell's membrane voltage that carries signals along excitable cells. Blocking sodium channels prevents the rising phase needed to generate and propagate it.
Tetrodontoidea: A superfamily of tetraodontiform fishes that includes pufferfish, porcupinefish, and ocean sunfish. The toxin's name derives from the pufferfish family Tetraodontidae within this broader fish group.
Voltage clamp: An electrophysiological technique that holds a cell's membrane voltage at a chosen value while measuring current. It lets researchers measure sodium currents before and after toxin application.
Tetrodotoxin poisoning: An illness caused by ingesting or otherwise being exposed to tetrodotoxin, often marked by numbness and paralysis. It is the direct clinical consequence of the toxin's sodium-channel blockade.
Saxitoxin: A potent neurotoxin that blocks voltage-gated sodium channels and can cause paralytic shellfish poisoning. It blocks the same channel pore through a distinct toxin with a different ecological history.
Symbiotic bacteria: Bacteria that live in close association with another organism, with effects that may benefit, harm, or neither. Bacteria have been proposed as sources of tetrodotoxin in some toxin-bearing animals.

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