The relationship between the entry of calcium ions and activation of calcium-activated potassium channels has been largely ignored until recently. It was assumed that calcium-activated potassium channels responded to global increases of intracellular calcium. It is now known that particular subtypes of calcium and calcium-activated potassium channels are functionally coupled. This coupling results from mechanisms that ensure an optimum distance separates channel subtypes. In this article, examples of channel co-localization in central neurons are presented, and how this association affects action potential duration and firing patterns is discussed. Finally, possible mechanisms underlying functional coupling are discussed as well as whether the association of channel subtypes can be regulated.
