Research
Print page Print page
Switch language
The Capital Region of Denmark - a part of Copenhagen University Hospital
Published

Reduced arterial vasodilatation in response to hypoxia impairs cerebral and peripheral oxygen delivery in hypertensive men

Research output: Contribution to journalJournal articleResearchpeer-review

DOI

  1. The impact of loading, unloading, ageing and injury on the human tendon

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Blood-brain barrier permeability measured using dynamic contrast-enhanced magnetic resonance imaging: a validation study

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Human brain blood flow and metabolism during isocapnic hyperoxia: the role of reactive oxygen species

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Lower body negative pressure to safely reduce intracranial pressure

    Research output: Contribution to journalJournal articleResearchpeer-review

  5. Sodium nitroprusside dilates cerebral vessels and enhances internal carotid artery flow in young men

    Research output: Contribution to journalJournal articleResearchpeer-review

  1. Muscle-liver substrate fluxes in exercising humans and potential effects on hepatic metabolism

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. The age-related reduction in cerebral blood flow affects vertebral artery more than internal carotid artery blood flow

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Role of spleen and liver for enhanced hemostatic competence following administration of adrenaline to humans

    Research output: Contribution to journalJournal articleResearchpeer-review

  • Igor A Fernandes
  • Marcos P Rocha
  • Monique O Campos
  • João D Mattos
  • Daniel E Mansur
  • Helena N M Rocha
  • Paulo A C Terra
  • Vinícius P Garcia
  • Natália G Rocha
  • Niels H Secher
  • Antonio C L Nóbrega
View graph of relations

KEY POINTS: Hypoxaemia evokes a repertoire of homeostatic adjustments that maintain oxygen supply to organs and tissues including the brain and skeletal muscles. Because hypertensive patients have impaired endothelial-dependent vasodilatation and an increased sympathetic response to arterial oxygen desaturation, we investigated whether hypertension impairs isocapnic hypoxia-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. In middle-aged hypertensive men, vertebral and femoral artery blood flow do not increase in response to isocapnic hypoxia, limiting brain and peripheral hyperaemia and oxygen supply. Increased chemoreflex-induced sympathetic activation impairs skeletal muscle perfusion and oxygen supply, whereas an attenuation of local vasodilatory signalling in the posterior cerebrovasculature reduced brain hyperperfusion of hypertensive middle-aged men in response to isocapnic hypoxia.

ABSTRACT: The present study investigated whether hypertension impairs isocapnic hypoxia (IH)-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. Oxygen saturation (oxymetry), mean arterial pressure (photoplethysmography) and muscle sympathetic nerve activity (MSNA; microneugraphy), as well as femoral artery (FA), internal carotid artery and vertebral artery (VA) blood flow (BF; Doppler ultrasound), were quantified in nine normotensive (NT) (aged 40 ± 11 years, systolic pressure 119 ± 7 mmHg and diastolic pressure 73 ± 6 mmHg) and nine hypertensive men (HT) (aged 44 ± 12 years, systolic pressure 152 ± 11 mmHg and diastolic pressure 90 ± 9 mmHg) during 5 min of normoxia (21% O2 ) and IH (10% O2 ). Total cerebral blood flow (tCBF), brain (CDO2 ) and leg (LDO2 ) oxygen delivery were estimated. IH provoked similar oxygen desaturation without changing mean arterial pressure. Internal carotid artery perfusion increased in both groups during IH. However, VA and FA BF only increased in NT. Thus, IH-induced increase in tCBF was smaller in HT. CDO2 only increased in NT and LDO2 decreased in HT. Furthermore, IH evoked a greater increase in HT MSNA. Changes in MSNA were inversely related to FA BF, LDO2 and end-tidal oxygen tension. In conclusion, hypertension disturbs regional and total cerebrovascular and peripheral responses to IH and consequently limits oxygen supply to the brain and skeletal muscle. Although increased chemoreflex-induced sympathetic activation may explain impaired peripheral perfusion, attenuated vasodilatory signalling in the posterior cerebrovasculature appears to be responsible for the small increase in tCBF when HT were exposed to IH.

Original languageEnglish
JournalThe Journal of physiology
Volume596
Issue number7
Pages (from-to)1167-1179
Number of pages13
ISSN0022-3751
DOIs
Publication statusPublished - 1 Apr 2018

ID: 56585496