Nitric oxide is the wonder drug of the '90s. When Furchgott and Zawadski¹ reported in 1980 that the endothelial lining of arteries was the source of an important messenger of vascular smooth muscle relaxation, who would have guessed that the messenger would turn out to be a noxious free radical gas contained in cigarette smoke? Identification of nitric oxide (NO) as the endothelial-derived mediator of vascular smooth muscle relaxation^2,3 launched a remarkably rapid and rewarding series of discoveries regarding regulation of vascular tone, followed by prompt transfer of this knowledge to the successful treatment of human disease.

NO first achieved celebrity status when it was named Science Magazine's "Molecule of the Year" in 1992.⁴ In that year came the news that NO is the world's leading cause of penile erection,⁵ an observation that spawned the development and distribution of Viagra as an effective remedy for erectile dysfunction.⁶ More accolades for NO came with the recent award of the Nobel Prize in Medicine to three American scientists whose pioneering research paved the way for NO's ascent to fame and fortune in a world where so many gases are regarded as mere pollutants. Now people everywhere are saying "yes" to "NO."

One of the most exciting developments in newborn medicine in the last decade has been the successful delivery of inhaled nitric oxide (iNO) to treat infants with persistent pulmonary hypertension,^7-9 a condition that commonly causes cyanosis from insufficient blood flow to the lungs. Patients with this life-threatening disorder often have an overgrowth of smooth muscle in their pulmonary circulation associated with increased vascular resistance that leads to systemic hypoxemia caused by shunting of de-oxygenated blood from the right atrium through the foramen ovale to the left atrium and from the pulmonary artery through the ductus arteriosus to the aorta. In such infants, . . . [Full Text of this Article]