Question

Tetrodotoxin blocks voltage-gated sodium channels and ouabain blocks sodium-potassium pumps. If you added both tetrodotoxin and ouabain to a solution containing neural tissue, what responses would you expect?
a. No effect, the substances counteract each other.
b. Immediate loss of resting potential.
c. slow decrease of resting potential and action potential amplitudes.
d. immediate loss of action potential with gradual loss of resting potential

Answer 1

A action potential is instigated by electrolytes, in this case let's limit ourselves to Na+ & K+ . Na+ is responsible for the depolarisation, while K+ is responsible for the repolarisation, these exchanges need to occure for action potential to occure. Now we've established that a "immediate loss of action potential" will occure.

Now for resting potential, a resting potential should be at -90 mV (If and i stress IF i remember correctly.) But since since you've blocked the the sodiumpotassium pump it will gradually decay. resulting in a "Gradual loss of resting potential".

Short answer: "d. immediate loss of action potential with gradual loss of resting potential"