Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. STKE, 27 April 2004
Vol. 2004, Issue 230, p. re6
[DOI: 10.1126/stke.2302004re6]


Carbon Monoxide: To Boldly Go Where NO Has Gone Before

Stefan W. Ryter, Danielle Morse, and Augustine M. K. Choi*

Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, MUH 628 NW, 3459 Fifth Avenue, Pittsburgh, PA 15213, USA.

Abstract: The discovery that nitric oxide (NO) has powerful vasoactive properties identical to those of endothelial-derived relaxing factor spawned a vast body of research investigating the physiological actions of small gas molecules. NO, which arises endogenously through the action of nitric oxide synthase (NOS) enzymes, is a highly reactive gas that plays important roles in the regulation of vascular and immune function. Carbon monoxide (CO), a similar yet much more chemically stable gas, occurs in nature as a product of the oxidation or combustion of organic materials. CO also arises in cells and tissues as a byproduct of heme oxygenase (HO) activity, which degrades heme to biliverdin-IXα. Like NO, CO acts as a vasorelaxant and may regulate other vascular functions such as platelet aggregation and smooth muscle proliferation. CO has also been implicated as a neurotransmitter in the central nervous system. HO-1, the inducible form of HO, confers cytoprotection against oxidative stress in vitro and in vivo. CO, when applied at low concentration, exerts potent cytoprotective effects mimicking those of HO-1 induction, including down-regulation of inflammation and suppression of apoptosis. Many of the effects of CO depend on the activation of guanylate cyclase, which generates guanosine 3',5'-monophosphate (cGMP), and the modulation of mitogen-activated protein kinase (MAPK) signaling pathways. This review highlights new advances in the interaction of CO with cellular signaling processes.

*Corresponding author. Phone, (412) 692-2117; fax, (412) 692-2260; e-mail, choiam{at}

Citation: S. W. Ryter, D. Morse, A. M. K. Choi, Carbon Monoxide: To Boldly Go Where NO Has Gone Before. Sci. STKE 2004, re6 (2004).

Read the Full Text

Nuclear Hormone Receptors, Metabolism, and Aging: What Goes Around Comes Around.
K. Pardee, J. Reinking, and H. Krause (2004)
Sci. Aging Knowl. Environ. 2004, re8
   Abstract »    Full Text »    PDF »

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882