Question

procaine (novocain) is a drug that blocks voltage - gated na⁺ channels. when present, what would happen in a neuron? multiple choice graded potentials are possible, but the neuron will not have the depolarizing phase of the action potential. neither graded potentials nor action potentials will occur. graded potentials are possible and the neuron will have the depolarizing phase of the action potential, but will be unable to repolarize. no phase of the action potential will be affected.

Explanation:

Graded potentials are generated by non - voltage - gated ion channels and are not affected by blocking voltage - gated Na⁺ channels. The depolarizing phase of an action potential in a neuron is due to the opening of voltage - gated Na⁺ channels. If these channels are blocked by procaine, the influx of Na⁺ ions that causes depolarization will not occur, but graded potentials can still happen.

Answer:

Graded potentials are possible, but the neuron will not have the depolarizing phase of the action potential.