Chronic intermittent hypoxia in humans during 28 nights results in blood pressure elevation and increased muscle sympathetic nerve activity
| Autor: | Geoffrey S. Gilmartin, J. W. Weiss, Renaud Tamisier, Mekkin E. Lynch |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Adult
Male medicine.medical_specialty Sympathetic nervous system Sympathetic Nervous System Physiology Ischemia Hemodynamics Blood Pressure Hyperemia Physiology (medical) Internal medicine medicine Humans Hypoxia Muscle Skeletal business.industry Sleep apnea Articles Hypoxia (medical) medicine.disease Obstructive sleep apnea Forearm medicine.anatomical_structure Blood pressure Anesthesia Circulatory system Cardiology Female medicine.symptom Cardiology and Cardiovascular Medicine business |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 299:H925-H931 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.00253.2009 |
| Popis: | Chronic intermittent hypoxia (CIH) is thought to be responsible for the cardiovascular disease associated with obstructive sleep apnea (OSA). Increased sympathetic activation, altered vascular function, and inflammation are all putative mechanisms. We recently reported (Tamisier R, Gilmartin GS, Launois SH, Pepin JL, Nespoulet H, Thomas RJ, Levy P, Weiss JW. J Appl Physiol 107: 17–24, 2009) a new model of CIH in healthy humans that is associated with both increases in blood pressure and augmented peripheral chemosensitivity. We tested the hypothesis that exposure to CIH would also result in augmented muscle sympathetic nerve activity (MSNA) and altered vascular reactivity contributing to blood pressure elevation. We therefore exposed healthy subjects between the ages of 20 and 34 yr ( n = 7) to 9 h of nocturnal intermittent hypoxia for 28 consecutive nights. Cardiovascular and hemodynamic variables were recorded at three time points; MSNA was collected before and after exposure. Diastolic blood pressure (71 ± 1.3 vs. 74 ± 1.7 mmHg, P < 0.01), MSNA [9.94 ± 2.0 to 14.63 ± 1.5 bursts/min ( P < 0.05); 16.89 ± 3.2 to 26.97 ± 3.3 bursts/100 heartbeats (hb) ( P = 0.01)], and forearm vascular resistance (FVR) (35.3 ± 5.8 vs. 55.3 ± 6.5 mmHg·ml−1·min·100 g tissue, P = 0.01) all increased significantly after 4 wk of exposure. Forearm blood flow response following ischemia of 15 min (reactive hyperemia) fell below baseline values after 4 wk, following an initial increase after 2 wk of exposure. From these results we conclude that the increased blood pressure following prolonged exposure to CIH in healthy humans is associated with sympathetic activation and augmented FVR. |
| Databáze: | OpenAIRE |
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