part of membrane depolarization membrane depolarization during cardiac muscle cell action potential Purkinje myocyte action potential membrane depolarization during Purkinje myocyte cell action potential The process in which Purkinje myocyte membrane potential changes in the depolarizing direction from the negative resting potential towards the positive membrane potential that will be the peak of the action potential. 2011-11-16T10:54:47Z GO:0086047 dph biological_process