ATP-sensitive K+ channels

ATP-sensitive K+ channels is a type of potassium channel containing Kir6.2 and sulfonylurea receptors, along with additional subunits.

It is usually closed in the heart; but when levels of ATP are reduced (as during ischemia), the channel opens. In the pancreatic islet beta cells the channel is usually open, but when ATP levels rise in response to the metabolism of high levels of glucose or amino acid metabolism the channel closes. This depolarizes the cell membrane, opens calcium ion channels and ultimately leads to an increase in insulin secretion. Defects in this pathway can lead to type 2 diabetes or hyperinsulinemia.