Section Review Cardiovascular & Renal: Recent advances in the pharmacology and therapeutic potential of potassium channel openers

Abstract

Potassium channels constitute the largest group of ion channels, the opening and closing of which result in membrane hyperpolarisation and depolarisation, respectively. This effectively modulates cellular excitability by controlling the open probability of voltage-sensitive calcium and sodium channels. Potassium channel openers are a diverse collection of drugs which act on K_ATP or BK_ca. Since both channels are non-inactivating, long-lasting inhibitory effects ensue. The site and mode of action of these drugs is not known for certain but, in the case of the K_ATP openers, it may be the so-called sulfonyl-urea receptor which is effectively a channel β-subunit. Openers of BK_ca are in the early stages of scientific study but drugs active at K_ATP are in various phases of clinical trial. One of these, nicorandil, is currently available for use in angina pectoris and levcromakalim has completed Phase III trials in hypertension. Of other possible applications, their use in the treatment of bronchial asthma and in the irritable bladder syndrome looks promising and various applications involving the central nervous system are under consideration.