Journal article
Contrasting effects of hypoxia and hypercapnia on ventilation and sympathetic activity in humans
Journal of applied physiology (1985), Vol.67(5), pp.2101-2106
11/1989
DOI: 10.1152/jappl.1989.67.5.2101
PMID: 2513316
Abstract
We compared the effects of isocapnic hypoxia (IHO) and hyperoxic hypercapnia (HC) on sympathetic nerve activity (SNA) recorded from a peroneal nerve in 13 normal subjects. HC caused greater increases in blood pressure (BP), minute ventilation (VE), and SNA [53 +/- 14% (SE) during HC vs. 21 +/- 7% during IHO; P less than 0.05]. Even at equivalent levels of VE, HC still elicited greater SNA than IHO. However, apnea during HC caused a lesser (P less than 0.05) increase in SNA (91 +/- 26% compared with apnea on room air) than apnea during IHO (173 +/- 50%). Hypercapnic hypoxia resulted in a greater absolute increase in VE (23.6 +/- 2.8 l/min) than the additive increases due to HC alone plus IHO alone (18.0 +/- 1.8 l/min, P less than 0.05). SNA also increased synergistically by 108 +/- 23% with the combined stimulus compared with the additive effect of HC alone plus IHO alone (68 +/- 19%; P less than 0.05). We conclude that 1) HC causes greater increases in VE and SNA than does hypoxia; 2) for the same increase in VE, hypercapnia still causes a greater increase in SNA than hypoxia; however, during apnea, hypoxia causes a much greater increase in SNA than hypercapnia; 3) the inhibitory influence of ventilation on SNA is greater during hypoxia (i.e., predominantly peripheral chemoreceptor stimulation) than hypercapnia (i.e., predominantly central chemoreceptor stimulation); and 4) combined hypoxia and hypercapnia have a synergistic effect on SNA as well as on VE.
Details
- Title: Subtitle
- Contrasting effects of hypoxia and hypercapnia on ventilation and sympathetic activity in humans
- Creators
- Virend K Somers - Department of Medicine, University of Iowa, Iowa CityAllyn L MarkDonald C ZavalaFrançois M Abboud
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.67(5), pp.2101-2106
- DOI
- 10.1152/jappl.1989.67.5.2101
- PMID
- 2513316
- NLM abbreviation
- J Appl Physiol (1985)
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Publisher
- United States
- Language
- English
- Date published
- 11/1989
- Academic Unit
- Molecular Physiology and Biophysics; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine
- Record Identifier
- 9984025471402771
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