<P> They also regulate cellular processes such as the secretion of hormones (e.g., insulin release from beta - cells in the pancreas) so their malfunction can lead to diseases (such as diabetes). </P> <P> There are four major classes of potassium channels: </P> <Ul> <Li> Calcium - activated potassium channel - open in response to the presence of calcium ions or other signalling molecules . </Li> <Li> Inwardly rectifying potassium channel - passes current (positive charge) more easily in the inward direction (into the cell). </Li> <Li> Tandem pore domain potassium channel - are constitutively open or possess high basal activation, such as the "resting potassium channels" or "leak channels" that set the negative membrane potential of neurons . </Li> <Li> Voltage - gated potassium channel - are voltage - gated ion channels that open or close in response to changes in the transmembrane voltage . </Li> </Ul> <Li> Calcium - activated potassium channel - open in response to the presence of calcium ions or other signalling molecules . </Li>

Are leak potassium channels different than voltage-gated potassium channels