title: Myoglobin functions in the heart.
abstract: The physiological role of myoglobin (Mb) within the heart depends on its oxygenation state. The myocardium exhibits a broad oxygen partial pressure (pO2) spectrum with a transmural gradient from the epicardial to the subendocardial layer, ranging from arterial values to an average of 19.3 mm Hg down to 0 mm Hg. The function of Mb as an O2 storage depot is well appreciated, especially during systolic compression. In addition, Mb controls myocardial nitric oxide (NO) homeostasis and thus modulates mitochondrial respiration under physiological and pathological conditions. We recently discovered the role of Mb as a myocardial O2 sensor; in its oxygenated state Mb scavenges NO, protecting the heart from the deleterious effects of excessive NO. Under hypoxia, however, deoxygenated Mb changes its role from an NO scavenger to an NO producer. The NO produced protects the cell from short phases of hypoxia and from myocardial ischemia/reperfusion injury. In this review we summarize the traditional and novel aspects of Mb and its (patho)physiological role in the heart.
authors.affiliation: University Hospital Düsseldorf, Medical Faculty, Division of Cardiology, Pulmonology, and Vascular Medicine, D-40225 Düsseldorf, Germany.
authors.forename: Ulrike B
authors.initials: UB
authors.lastname: Hendgen-Cotta
authors.affiliation: University Hospital Düsseldorf, Medical Faculty, Division of Cardiology, Pulmonology, and Vascular Medicine, D-40225 Düsseldorf, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Kelm
authors.affiliation: University Hospital Düsseldorf, Medical Faculty, Division of Cardiology, Pulmonology, and Vascular Medicine, D-40225 Düsseldorf, Germany. Electronic address: Tienush.Rassaf@med.uni-duesseldorf.de.
authors.forename: Tienush
authors.initials: T
authors.lastname: Rassaf
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000502:physiology*; D019069:Cell Respiration; D003331:Coronary Vessels / Q000502:physiology; D006321:Heart; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D051379:Mice; D015428:Myocardial Reperfusion Injury / Q000473:pathology; D009211:Myoglobin / Q000502:physiology*; D009569:Nitric Oxide / Q000633:toxicity*; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption / Q000502:physiology*; D030421:Peroxynitrous Acid / Q000633:toxicity
chemical_list: D009211:Myoglobin; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D010100:Oxygen
keywords: Free radicals; Myoglobin; Nitric oxide; Nitrite; Oxygen