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          Institute: MPI für Herz- und Lungenforschung (W. G. Kerckhoff Institut)     Collection: Publikationen des W. G. Kerckhoff-Instituts     Display Documents

ID: 559587.0, MPI für Herz- und Lungenforschung (W. G. Kerckhoff Institut) / Publikationen des W. G. Kerckhoff-Instituts
Mitochondrial cytochrome redox states and respiration in acute pulmonary oxygen sensing
Authors:Sommer, N.; Pak, O.; Schorner, S.; Derfuss, T.; Krug, A.; Gnaiger, E.; Ghofrani, H. A.; Schermuly, R. T.; Huckstorf, C.; Seeger, W.; Grimminger, F.; Weissmann, N.
Title of Journal:Eur Respir J
Issue / Number:5
Start Page:1056
End Page:66
Audience:Not Specified
Abstract / Description:Hypoxic pulmonary vasoconstriction (HPV) is an essential mechanism to optimise lung gas exchange. We aimed to decipher the proposed oxygen sensing mechanism of mitochondria in HPV. Cytochrome redox state was assessed by remission spectrophotometry in intact lungs and isolated pulmonary artery smooth muscle cells (PASMC). Mitochondrial respiration was quantified by high-resolution respirometry. Alterations were compared with HPV and hypoxia-induced functional and molecular readouts on the cellular level. Aortic and renal arterial smooth muscle cells (ASMC and RASMC, respectively) served as controls. The hypoxia-induced decrease of mitochondrial respiration paralleled HPV in isolated lungs. In PASMC, reduction of respiration and mitochondrial cytochrome c and aa3 (complex IV), but not of cytochrome b (complex III) matched an increase in matrix superoxide levels as well as mitochondrial membrane hyperpolarisation with subsequent cytosolic calcium increase. In contrast to PASMC, RASMC displayed a lower decrease in respiration and no rise in superoxide, membrane potential or intracellular calcium. Pharmacological inhibition of mitochondria revealed analogous kinetics of cytochrome redox state and strength of HPV. Our data suggest inhibition of complex IV as an essential step in mitochondrial oxygen sensing of HPV. Concomitantly, increased superoxide release from complex III and mitochondrial membrane hyperpolarisation may initiate the cytosolic calcium increase underlying HPV.
Free Keywords:Animals; Anoxia/*metabolism; Aorta/cytology; Cell Respiration/physiology; Cells, Cultured; Cytochromes/*metabolism; Cytochromes b/metabolism; Cytochromes c/metabolism; Electron Transport Complex IV/metabolism; Female; Lung/blood supply/*metabolism; Male; Membrane Potential, Mitochondrial/physiology; Mitochondria/*metabolism; Muscle, Smooth, Vascular/cytology/*metabolism; Oxidation-Reduction; Oxygen Consumption/*physiology; Pulmonary Circulation/physiology; Rabbits; Renal Artery/cytology; Spectrophotometry; Superoxides/metabolism; Vasoconstriction/physiology
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für physiologische und klinische Forschung
External Affiliations:University of Giessen Lung Center, Gaffkystrasse 11, 35392 Giessen, Germany. Norbert.Weissmann@uglc.de
Identifiers:ISSN:1399-3003 (Electronic) 0903-1936 (Linking)
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