Question

Some cells of the body spontaneously generate action potentials. For these cells, they do not remain at a given resting membrane potential, instead suddenly depolarizing to threshold. The mechanism of spontaneous depolarization results from a combination of changing gated channel permeability and intracellular protein levels (second messengers, such as cAMP). Medications aimed at delaying or accelerating this spontaneous depolarization come in many different forms, targeting different aspects of these channels or second messenger systems. Answer the following questions.

If one of the ion channels involved in spontaneous depolarization are K+ channels, are they spontaneously opening or closing to cause depolarization? Explain.