Many species of pufferfish, or fugu, harbor bacteria that produce a neurotoxin known as tetrodotoxin. The toxin
tends to accumulate in the liver and gonads of the fish. Fugu is also a Japanese delicacy served by highly trained
chefs. If not prepared correctly, portions of the toxic organs can be ingested and cause tetrodotoxin poisoning.
The toxin works by blocking the voltage-gated Na+ channels of neurons.
a. Predict the symptoms of tetrodotoxin poisoning based on what you know about the functions of voltage-
gated Na+ channels in neurons.
b. Predict the effect that tetrodotoxin would have on muscle fiber action potentials. Would it affect end-plate
potentials at the motor end plate? Why or why not?
c. Lithium is a drug that reduces the permeability of the neuronal axolemma to Na+. Would this drug be
beneficial or harmful for a person suffering from tetrodotoxin poisoning? Explain based on how it would
affect neuronal action potentials.
A. Tetradotoxin mainly binds to the voltage gated sodium chanels. It blocks the flow of sodium ions... View the full answer