Tetrodotoxin is a toxin that blocks voltage-gated sodium channels.What effect does this substance have on the function of neurons?
A) Neurons depolarize more rapidly.
B) Action potentials lack a repolarization phase.
C) The absolute refractory period is shorter than normal.
D) The neuron is not able to propagate action potentials.
E) The toxin does not interfere with neuron function because the voltage-regulated sodium channels would still function.

Question

Quizplus · Accepted Answer

Tetrodotoxin blocks voltage-gated sodium channels, which are responsible for the depolarization phase of action potentials in neurons. Without these channels, the neuron is unable to propagate action potentials and therefore cannot function properly. Choices A, B, and C are incorrect because they suggest an increase in neuronal activity, when in fact tetrodotoxin has the opposite effect. Choice E is also incorrect because the toxin clearly interferes with the function of voltage-gated sodium channels that are necessary for normal neuronal function.

Tetrodotoxin Is a Toxin That Blocks Voltage-Gated Sodium Channels