Figure 1. A working model of the ZG pacemaker .

At the start of the oscillatory cycle (V _m = −85 mV), depolarizing conductance(s) (X_v) elicit the opening of low voltage‐activated Ca_v3.2 channels which further depolarize V _m and enable the opening of high voltage‐activated Ca_v1.3 channels. Ca²⁺ influx and a reduced V _m recruits the activity of Ca²⁺‐dependent K⁺ channels that return V _m to −85 mV to begin another oscillatory cycle.