Spontaneous APs occur in bursts in CCs from β2 KO mice. (A) Traces show spontaneous firing from WT mouse CCs expressing inactivating BK current. Top trace shows 35 s of continuous activity, middle trace shows 5 s of activity on a faster time pace (red segment on top trace), and the bottom shows a set of eight APs aligned on the time point at which the AP reaches 0 mV. (B) Traces show spontaneous activity from a CC with largely noninactivating BK (BK_s) current. (C) Traces show spontaneous APs from a CC from a kcnma1^−/− mouse. (D) Traces show bursting, slow-wave activity from a CC from a kcnmb2^−/− mouse. (E) Spontaneous activity from another kcnmb2^−/− CC. (F) Traces illustrate spontaneous activity in a WT CC with primarily noninactivating BK current, in which occasional slow-wave burst activity was observed. All recordings are from cells in adrenal medullary slices.