Question

Tetraethylammonium (TEA) is a potent neurotoxin that results in death from respiratoryfailure within 10 to 30 minutes. When a neuron is incubated with TEA, researchers observed thataction potentials could be generated, but the membrane potential remained positive and neverreturned to the resting membrane potential. What channel is TEA likely acting on?

A) voltage-gated sodium channelsB) voltage-gated potassium channelsC) sodium potassium pumpsD) chloride channels

Answer 1

Answer: B voltage-gated potassium channels

Explanation:#

Tetraethylammonium is a pH- potassium channel blocker.

Therefore, it prevents the escape of potassium ions from the axoplasm, which makes it ( axoplam) positive from the rise in potassium ions concentration , since potassium ion is positive charged and intracellular ion . This initiate repolarization which returns to membrane state potential.

Since it is pH -potassium ion blocker; it does not affect the voltage-gated sodium ion channels, so action potential can occur. But after the sodium gated channels were closed,action potential drops but the concentration of potassium rises because :

1. They are naturally intracellular ions

2. They cannot leave the axoplasm because the channels has been shut. Therefore this stabilizes the membrane potential