Three Americans, including a UCLA pharmacologist, were awarded the 1998 Nobel Prize for Physiology or Medicine on Monday for their discovery that nitric oxide--a common gas better known as an air pollutant--transmits signals within the human body.

UCLA's Louis J. Ignarro, 57, will share the $955,500 prize with Robert F. Furchgott, 82, of the State University of New York in Brooklyn and Dr. Ferid Murad, 62, of the University of Texas medical school in Houston.

"The discovery of nitric oxide and its function is one of the most important in the history of cardiovascular medicine," said Dr. Valentin Fuster, president of the American Heart Assn. "It has allowed us to improve the treatment of certain patients" and will probably lead to the discovery of new ways to treat high blood pressure and heart attacks, he added.