Journal article
Effect of acute hypoxia on vascular responsiveness in man. I. Responsiveness to lower body negative pressure and ice on the forehead. II. Responses to norepinephrine and angiotensin. 3. Effect of hypoxia and hypocapnia
The Journal of clinical investigation, Vol.49(6), pp.1252-1265
06/1970
DOI: 10.1172/JCI106338
PMID: 4316225
Abstract
An effect of hypoxemia on vascular responsiveness and blood pressure regulation has not been demonstrated in man. The response of forearm resistance vessels to several vasoconstrictor stimuli was compared during normoxia and acute hypoxia. Forearm vasoconstrictor responses to lower body negative pressure and to the application of ice to the forehead, which are neurogenic stimuli, were decreased during acute hypoxia. Lower body negative pressure caused a decrease in mean arterial pressure during hypoxia, but not during normoxia. Because norepinephrine is the neurotransmitter released during reflex vasoconstriction, we considered the possibility that decreased responsiveness to norepinephrine might be one mechanism for diminished responses to lower body negative pressure and ice on the forehead during hypoxia. Hypoxia decreased the response of forearm resistance vessels to infusions of norepinephrine and angiotensin into the brachial artery. In addition, the effectiveness of intravenous infusions of norepinephrine in elevating mean arterial pressure was decreased during hypoxia. Since exposure to acute hypoxia stimulates hyperventilation and hypocapnia, experiments were done to determine the contribution of hypocapnia during hypoxia to the decreased vasoconstriction. The results indicate that hypocapnia may diminish the vascular response to some stimuli, but the reduction in oxygen appears to be the primary mechanism for decreased vasoconstrictor responses during acute hypoxia.
Details
- Title: Subtitle
- Effect of acute hypoxia on vascular responsiveness in man. I. Responsiveness to lower body negative pressure and ice on the forehead. II. Responses to norepinephrine and angiotensin. 3. Effect of hypoxia and hypocapnia
- Creators
- D D HeistadR C Wheeler
- Resource Type
- Journal article
- Publication Details
- The Journal of clinical investigation, Vol.49(6), pp.1252-1265
- Publisher
- American Society for Clinical Investigation
- DOI
- 10.1172/JCI106338
- PMID
- 4316225
- ISSN
- 0021-9738
- eISSN
- 1558-8238
- Language
- English
- Date published
- 06/1970
- Academic Unit
- Cardiovascular Medicine; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984040202002771
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