A change in the MEMBRANE POTENTIAL of a cell that makes it less negative. In the case of excitable cells, depolarization usually occurs by opening an ION CHANNEL to allow positive charged ions that are abundant outside the cell, such as sodium and...

In biology, depolarization is a decrease in the absolute value of a cell's membrane potential. Thus, changes in membrane voltage in which the membrane potential becomes less positive or less negative are both depolarizations. In neurons and some other...