Objective: Intracellular magnesium ions (Mg 2+ ) are important in the regulation of a wide range of cellular metabolic processes and modulation of a variety of ion channels. Mg 2+ deficiency has been implicated in the aetiology of various cardiovascular diseases. However, potential targets and mechanisms of action of Mg 2+ in the cardiovascular system remain poorly understood. We therefore investigated the effect of Mg 2+ on the voltage-gated K + (KV) channels in rat aortic myocytes (RAMs).