Short-term intermittent hypoxia enhances sympathetic responses to continuous hypoxia in humans
| Autor: | Urs A, Leuenberger, Cynthia S, Hogeman, Sadeq A, Quraishi, Sadeq, Quraishi, Latoya, Linton-Frazier, Kristen S, Gray |
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| Rok vydání: | 2007 |
| Předmět: |
Adult
Male medicine.medical_specialty Sympathetic nervous system Sympathetic Nervous System Time Factors Physiology Sympathetic nerve Hyperoxia Physiology (medical) Internal medicine medicine Humans Hypoxia Sleep Apnea Obstructive business.industry Hemodynamics Sleep apnea Intermittent hypoxia Hypoxia (medical) medicine.disease Chemoreceptor Cells Oxygen Obstructive sleep apnea Autonomic nervous system Blood pressure medicine.anatomical_structure Anesthesia Cardiology Female medicine.symptom Pulmonary Ventilation business |
| Zdroj: | Journal of Applied Physiology. 103:835-842 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.00036.2007 |
| Popis: | Short-term intermittent hypoxia leads to sustained sympathetic activation and a small increase in blood pressure in healthy humans. Because obstructive sleep apnea, a condition associated with intermittent hypoxia, is accompanied by elevated sympathetic activity and enhanced sympathetic chemoreflex responses to acute hypoxia, we sought to determine whether intermittent hypoxia also enhances chemoreflex activity in healthy humans. To this end, we measured the responses of muscle sympathetic nerve activity (MSNA, peroneal microneurography) to arterial chemoreflex stimulation and deactivation before and following exposure to a paradigm of repetitive hypoxic apnea (20 s/min for 30 min; O2 saturation nadir 81.4 ± 0.9%). Compared with baseline, repetitive hypoxic apnea increased MSNA from 113 ± 11 to 159 ± 21 units/min ( P = 0.001) and mean blood pressure from 92.1 ± 2.9 to 95.5 ± 2.9 mmHg ( P = 0.01; n = 19). Furthermore, compared with before, following intermittent hypoxia the MSNA (units/min) responses to acute hypoxia [fraction of inspired O2 (FiO2) 0.1, for 5 min] were enhanced (pre- vs. post-intermittent hypoxia: +16 ± 4 vs. +49 ± 10%; P = 0.02; n = 11), whereas the responses to hyperoxia (FiO2 0.5, for 5 min) were not changed significantly ( P = NS; n = 8). Thus 30 min of intermittent hypoxia is capable of increasing sympathetic activity and sensitizing the sympathetic reflex responses to hypoxia in normal humans. Enhanced sympathetic chemoreflex activity induced by intermittent hypoxia may contribute to altered neurocirculatory control and adverse cardiovascular consequences in sleep apnea. |
| Databáze: | OpenAIRE |
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