Voltage-gated K+ channels (KV channels) are encoded by theKCNxgene family and have such a wide range of properties that it is necessary to identify the precise expression profile that is instrumental in governing the electrical phenotype of a cell and its response to extrinsic factors. Real-time quantitative RT-PCR methodology has been developed and validated for specific RNA species in vascular smooth muscle cells. We have shown that most of theKCNAgene family, encoding the major KV α1 subunits, was markedly up-regulated in the resistance artery compared to the thoracic aorta, in line with reported patch-clamp recordings. Thus quantitative real-time RT-PCR data can be translated into physiological response.