Tetrodotoxin

Tetrodotoxin, also called Fugu poison, maculotoxin, spheroidine and TTX, is a neurotoxin that selectively targets the voltage-gated sodium channel of the nerve cells membrane.

According to the CDC, the main route of exposure to tetrodotoxin is through ingestion of certain species of fish, shellfish, octopi or amphibians. By targeting the neurons, it triggers partial to total muscle paralysis, which in some cases can be fatal.

Figure 1: Molecular structure of Tetradotoxin

Tetrodotoxin binds to the neurotoxin receptor site 1 of the α alpha subunit of the sodium ion channel, connecting to the pore loops and blocking the ion transfer.

By blocking the voltage-gated sodium channel, tetrodotoxin prevents the depolarization of the membrane and the propagation of an action potential, thus effectively preventing the transmission of information through the neuron.