What effect do Class 1B sodium channel blockers have on action potential?

What effect do Class 1B sodium channel blockers have on action potential?

• A. Prolong action potential duration
• B. Shorten action potential duration
• C. Have no measurable effect
• D. Increase conduction velocity

Answer: (B)

Class 1B sodium channel blockers primarily function by stabilizing the inactive state of the sodium channels, which subsequently decreases the influx of sodium during the depolarization phase of action potentials. This effect is particularly pronounced in tissues that are frequently depolarizing, such as ventricles in the heart. By reducing sodium influx, these medications speed up the repolarization phase, which ultimately leads to a shorter action potential duration. The shortening of action potential duration is significant in clinical settings, especially in managing certain arrhythmias, as it can help restore a more normalized electrical activity in the heart. Thus, Class 1B sodium channel blockers effectively facilitate a quicker recovery and reduce the overall time that the cell is in the depolarized state.

Class 1B sodium channel blockers primarily function by stabilizing the inactive state of the sodium channels, which subsequently decreases the influx of sodium during the depolarization phase of action potentials. This effect is particularly pronounced in tissues that are frequently depolarizing, such as ventricles in the heart. By reducing sodium influx, these medications speed up the repolarization phase, which ultimately leads to a shorter action potential duration.

The shortening of action potential duration is significant in clinical settings, especially in managing certain arrhythmias, as it can help restore a more normalized electrical activity in the heart. Thus, Class 1B sodium channel blockers effectively facilitate a quicker recovery and reduce the overall time that the cell is in the depolarized state.