Some drugs modulate the activity of ion channels. For example, Novocain somewhat inhibits the opening of sodium channels. What happens to the threshold of a sensory neuron if this drug is used?
A) It will take less stimulation to reach threshold.
B) It will take more stimulation to reach threshold.
C) Threshold will not change.
D) The nerve will not function and will die off.

Question

Quizplus · Accepted Answer

Novocain inhibits the opening of sodium channels. Sodium channels are responsible for depolarizing the membrane potential and initiating an action potential. If the opening of sodium channels is inhibited, more stimulation will be needed to reach the threshold for an action potential to be initiated. Therefore, the threshold for a sensory neuron will increase with the use of Novocain.

Some Drugs Modulate the Activity of Ion Channels