Pulmonary hypertension, nitric oxide and nitric oxide-releasing compounds

Nitric oxide (NO) is an important molecule in the mammalian cardiovascular system and the elucidation of its biological role has led to the awarding of a Nobel prize in medicine. There have been many significant discoveries in NO biology over the past two decades and translation of these developments from bench to bedside has allowed an explosion of therapies for pulmonary hypertension. This article provides an overview of the NO pathway in the pulmonary circulation in maintenance of normal vascular tone as well as its dysregulation in pulmonary hypertension, and a discussion of therapies based on inhaled NO or manipulation of its downstream signaling pathways. Several therapies such as phosphodiesterase inhibitors are already in use, and various experimental therapies are also discussed.