FoundationalConceptsNeuroscience

oO

HO ~ -OH

HO OH

HNN OH

HN

Tetrodotoxin

Figure 8.1. Theophrastus Philippus Aureolus Bombastus von Hohenheim, bet-
ter known as Paracelsus (1493-1541). Engravings from the 1500s: on the left
Paracelsus is depicted at around thirty years of age, on the right he is shown
shortly before his death.

The shape of TTX promotes its sticking to the outside surface
of the voltage-gated sodium channel in such a way that it blocks the
pore through which sodium ions pass when the channel opens. This
compound is such an effective blocker of voltage-gated Na channels
that even a very small amount of it is highly poisonous. Blocking Na