SK channels are on the move.

Small-conductance Ca(2+)-activated K(+) channels (SK channels) underlie the medium duration after hyperpolarization that follows single or trains of action potentials in many types of neurons. Three subtypes of SK subunits, SK1 (K(Ca)2.1), SK2 (K(Ca)2.2) and SK3 (K(Ca)2.3), have been cloned and are expressed differentially within the central nervous system (CNS). A paper in this issue of BJP reports the discovery of the first example of a positive modulator displaying not only selectivity for SK channels over other channels, but also a subtype selectivity among SK and analogous channels (SK3>SK2>>>SK1=IK). Together with other recent progress in the field, this finding enriches the repertoire of tools available to test the hypothesis that SK channels may be targets for future CNS drugs.