Nitric oxide signaling in the cardiovascular system: implications for heart failure.
OBJECTIVE
The role played by nitric oxide (NO) in cardiovascular physiology remains highly controversial. Following the discovery that NO is the prototypic endothelium-derived relaxing factor, this signaling molecule was implicated as possessing many other biological actions within the cardiovascular system, including effects on cardiac contraction, relaxation, and energetics. Here, we discuss new concepts regarding NO signaling, its effector pathways, and interactions between NO and the redox milieu within a framework of cardiac physiology and pathophysiology.


RESULTS
Major recent insights that have advanced understanding of the mechanisms of NO bioactivity include the following. (1) NO acts in subcellular signaling compartments or modules. (2) S-nitrosylation (covalent modification of cysteine thiol moieties) of proteins represents a prototypic second messenger signaling mode in biologic systems. (3) Reactive oxygen and nitrogen species work together to facilitate signaling. (4) Disruption of physiologic signaling can occur by either increased formation of reactive oxygen species or decreased production of reactive nitrogen species, a situation of nitroso-redox imbalance.


CONCLUSIONS
These insights, which challenge classically held views that NO acts as a freely diffusible molecule regulated primarily by concentration and exerting signaling primarily through cyclic GMP production, offer a new perspective on the pathophysiology and treatment of congestive heart failure.
Saraiva
Roberto M
RM
Cardiology Division, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
Hare
Joshua M
JM
D000426:Alcohol Dehydrogenase; D000818:Animals; D005260:Female; D005980:Glutathione Reductase / Q000378:metabolism; D006333:Heart Failure / Q000378:metabolism* / Q000628:therapy; D006801:Humans; D008297:Male; D051379:Mice; D009569:Nitric Oxide / Q000502:physiology*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction
D017382:Reactive Oxygen Species; D009569:Nitric Oxide; C483598:Adh5 protein, mouse; D000426:Alcohol Dehydrogenase; C496320:NOS1 protein, human; C496314:NOS3 protein, human; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D005980:Glutathione Reductase