Book excerpt: Nitric oxide (NO) is a gas that transmits signals in an organism. Signal transmission by a gas that is produced by one cell and which penetrates through membranes and regulates the function of another cell represents an entirely new principle for signaling in biological systems. NO is a signal molecule of key importance for the cardiovascular system acting as a regulator of blood pressure and as a gatekeeper of blood flow to different organs. NO also exerts a series of other functions, such as acting a signal molecule in the nervous system and as a weapon against infections. NO is present in most living creatures and made by many different types of cells. NO research has led to new treatments for treating heart as well as lung diseases, shock, and impotence. Scientists are currently testing whether NO can be used to stop the growth of cancerous tumors, since the gas can induce programmed cell death, apoptosis. This book is the first comprehensive text on nitric oxide to cover all aspects--basic biology, chemistry, pathobiology, effects on various disease states, and therapeutic implications. - Edited by Nobel Laureate Louis J. Ignarro, editor of the Academic Press journal, Nitric Oxide - Authored by world experts on nitric oxide - Includes an overview of basic principles of biology and chemical biology - Covers principles of pathobiology, including the nervous system, cardiovascular function, pulmonary function, and immune defense