Potassium (K⁺) channels regulate cell membrane potential and modulate a number of important cellular functions. K⁺ voltage-gated channel subfamily A member 10 (KCNA10) also known as K_V1.8 is a voltage-gated K⁺ (K_V) channel gene related to the Shaker family of K⁺ channels that includes eight members (K_V1.1- K_V1.8)¹. K_V1.8 contains six membrane-spanning domains with a shaker-type repeat in the fourth segment and a pore (P) region. Its most distinguishing feature is the presence of a putative cyclic nucleotide-binding (CNB) domain at the COOH terminus². It is specifically regulated by cGMP and postulated to mediate the effects of substances that increase intracellular cGMP¹. The channel displays an unusual inhibitor profile, because in addition to being blocked by classical K⁺ channel blockers, it is also sensitive to inhibitors of cyclic nucleotide gated cation channel such as verapamil and pimozide³.

K_V1.8 is detected in kidney, heart, and aorta by northern blot and postulated to participate in renal K⁺ metabolism and to regulate vascular tone³. A recent study showed that a null mutation of mouse KCNA10 causes significant vestibular and mild hearing dysfunction⁴. In addition KCNA10 has been associated with Long QT syndrome (LQTS), an arrhythmogenic disorder characterized by prolongation of the QT interval on electrocardiograms (ECGs)⁵.