| Ventilatory, hemodynamic, sympathetic nervous system, and vascular reactivity changes after recurrent nocturnal sustained hypoxia in humans. | |
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MedLine Citation:
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PMID: 18539753 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Recurrent and intermittent nocturnal hypoxia is characteristic of several diseases including chronic obstructive pulmonary disease, congestive heart failure, obesity-hypoventilation syndrome, and obstructive sleep apnea. The contribution of hypoxia to cardiovascular morbidity and mortality in these disease states is unclear, however. To investigate the impact of recurrent nocturnal hypoxia on hemodynamics, sympathetic activity, and vascular tone we evaluated 10 normal volunteers before and after 14 nights of nocturnal sustained hypoxia (mean oxygen saturation 84.2%, 9 h/night). Over the exposure, subjects exhibited ventilatory acclimatization to hypoxia as evidenced by an increase in resting ventilation (arterial Pco(2) 41.8 +/- 1.5 vs. 37.5 +/- 1.3 mmHg, mean +/- SD; P < 0.05) and in the isocapnic hypoxic ventilatory response (slope 0.49 +/- 0.1 vs. 1.32 +/- 0.2 l/min per 1% fall in saturation; P < 0.05). Subjects exhibited a significant increase in mean arterial pressure (86.7 +/- 6.1 vs. 90.5 +/- 7.6 mmHg; P < 0.001), muscle sympathetic nerve activity (20.8 +/- 2.8 vs. 28.2 +/- 3.3 bursts/min; P < 0.01), and forearm vascular resistance (39.6 +/- 3.5 vs. 47.5 +/- 4.8 mmHg.ml(-1).100 g tissue.min; P < 0.05). Forearm blood flow during acute isocapnic hypoxia was increased after exposure but during selective brachial intra-arterial vascular infusion of the alpha-blocker phentolamine it was unchanged after exposure. Finally, there was a decrease in reactive hyperemia to 15 min of forearm ischemia after the hypoxic exposure. Recurrent nocturnal hypoxia thus increases sympathetic activity and alters peripheral vascular tone. These changes may contribute to the increased cardiovascular and cerebrovascular risk associated with clinical diseases that are associated with chronic recurrent hypoxia. |
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Authors:
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Geoffrey S Gilmartin; Renaud Tamisier; Matthew Curley; J Woodrow Weiss |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2008-06-06 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 295 ISSN: 0363-6135 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2008 Aug |
Date Detail:
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Created Date: 2008-08-08 Completed Date: 2008-09-25 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H778-85 Citation Subset: IM |
Affiliation:
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Laboratoire d'Exploration Fonctionnelle Respiratoire, Centre Hospitalier Universitaire de Grenoble BP 217, 38043 Grenoble Cedex 9, France. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Acclimatization Adrenergic alpha-Antagonists / administration & dosage Adult Anoxia / physiopathology* Blood Pressure Circadian Rhythm* Female Forearm / blood supply* Heart Rate Hemodynamics* / drug effects Humans Hyperemia / physiopathology Infusions, Intra-Arterial Male Muscle, Skeletal / innervation* Phentolamine / administration & dosage Pulmonary Ventilation* Regional Blood Flow Sympathetic Nervous System / physiopathology* Time Factors Vascular Resistance* |
| Grant Support | |
ID/Acronym/Agency:
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HL-072648/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic alpha-Antagonists; 50-60-2/Phentolamine |
| Comments/Corrections | |
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