Action potentials and insulin secretion: new insights into the role of Kv channels

Coordinated electrical activity allows pancreatic β-cells to respond to secretagogues with calcium entry followed by insulin secretion. Metabolism of glucose affects multiple membrane proteins including ion channels, transporters and pumps that collaborate in a cascade of electrical activity resulting in insulin release. Glucose induces β-cell depolarization resulting in the firing of action potentials (APs), which are the primary electrical signal of the β-cell. They are shaped by orchestrated activation of ion channels. Here we give an overview of the voltage-gated potassium (Kv) channels of the β-cell, which are responsible in part for the falling phase of the AP, and how their regulation affects insulin secretion. β cells contain several Kv channels allowing dynamic integration of multiple signals on repolarization of glucose-stimulated APs. Recent studies on Kv channel regulation by cAMP and arachidonic acid and on the Kv2.1 null mouse have greatly increased our understanding of β-cell excitation–secretion coupling.