action potential Action potentials typically propagate across excitable membranes. This class covers both action potentials that propagate and those that fail to do so. GO:0001508 biological_process A process in which membrane potential cycles through a depolarizing spike, triggered in response to depolarization above some threshold, followed by repolarization. This cycle is driven by the flow of ions through various voltage gated channels with different thresholds and ion specificities. regulation of membrane potential