K Ca 2 and K Ca 3.1 Channels in the Airways: A New Therapeutic Target.

K + channels are involved in many critical functions in lung physiology. Recently, the family of Ca 2+ -activated K + channels (K Ca ) has received more attention, and a massive amount of effort has been devoted to developing selective medications targeting these channels. Within the family of K Ca channels, three small-conductance Ca 2+ -activated K + (K Ca 2) channel subtypes, together with the intermediate-conductance K Ca 3.1 channel, are voltage-independent K + channels, and they mediate Ca 2+ -induced membrane hyperpolarization. Many K Ca 2 channel members are involved in crucial roles in physiological and pathological systems throughout the body. In this article, different subtypes of K Ca 2 and K Ca 3.1 channels and their functions in respiratory diseases are discussed. Additionally, the pharmacology of the K Ca 2 and K Ca 3.1 channels and the link between these channels and respiratory ciliary regulations will be explained in more detail. In the future, specific modulators for small or intermediate Ca 2+ -activated K + channels may offer a unique therapeutic opportunity to treat muco-obstructive lung diseases.