K_Ca2.3 is a member of the Ca²⁺-activated K⁺ channel family with small conductance that includes K_Ca2.1 (SK1) and K_Ca2.2 (SK2). The channel is voltage insensitive and is activated by intracellular Ca²⁺ in the submicromolar range. K_Ca2.3 is predominantly expressed in the nervous system although expression in endothelial cells, heart and liver have been described. K_Ca2.3 is involved in the control of firing rate and subsequent dopamine secretion from midbrain dopaminergic neurons. Since malfunction of these neurons is involved in several pathological disorders, such as Parkinson’s Disease and Schizophrenia, modulators of K_Ca2.3 channels have been proposed to be of therapeutic value in these diseases.