Chemoreceptors and cardiovascular control in acute and chronic systemic hypoxia
| Autor: | Marshall Jm |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
medicine.medical_specialty
Sympathetic nervous system Adenosine Physiology Immunology Biophysics Peripheral chemoreceptors Vasodilation Biology chemoreceptors Biochemistry Cardiovascular Physiological Phenomena Norepinephrine Internal medicine medicine Humans General Pharmacology Toxicology and Pharmaceutics Hypoxia Muscle Skeletal lcsh:QH301-705.5 lcsh:R5-920 hypoxia General Neuroscience Cell Biology General Medicine Sudden infant death syndrome Hypoxia (medical) vasodilatation Chemoreceptor Cells Oxygen Endocrinology medicine.anatomical_structure lcsh:Biology (General) adenosine Vasoconstriction Acute Disease Chronic Disease noradrenaline Reflex medicine.symptom lcsh:Medicine (General) medicine.drug |
| Zdroj: | Brazilian Journal of Medical and Biological Research, Volume: 31, Issue: 7, Pages: 863-888, Published: JUL 1998 Brazilian Journal of Medical and Biological Research, Vol 31, Iss 7, Pp 863-888 (1998) Brazilian Journal of Medical and Biological Research, Vol 31, Iss 7, p 863 (1998) Brazilian Journal of Medical and Biological Research v.31 n.7 1998 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC |
| ISSN: | 0100-879X |
| DOI: | 10.1590/s0100-879x1998000700002 |
| Popis: | This review describes the ways in which the primary bradycardia and peripheral vasoconstriction evoked by selective stimulation of peripheral chemoreceptors can be modified by the secondary effects of a chemoreceptor-induced increase in ventilation. The evidence that strong stimulation of peripheral chemoreceptors can evoke the behavioural and cardiovascular components of the alerting or defence response which is characteristically evoked by novel or noxious stimuli is considered. The functional significance of all these influences in systemic hypoxia is then discussed with emphasis on the fact that these reflex changes can be overcome by the local effects of hypoxia: central neural hypoxia depresses ventilation, hypoxia acting on the heart causes bradycardia and local hypoxia of skeletal muscle and brain induces vasodilatation. Further, it is proposed that these local influences can become interdependent, so generating a positive feedback loop that may explain sudden infant death syndrome (SIDS). It is also argued that a major contributor to these local influences is adenosine. The role of adenosine in determining the distribution of O2 in skeletal muscle microcirculation in hypoxia is discussed, together with its possible cellular mechanisms of action. Finally, evidence is presented that in chronic systemic hypoxia, the reflex vasoconstrictor influences of the sympathetic nervous system are reduced and/or the local dilator influences of hypoxia are enhanced. In vitro and in vivo findings suggest this is partly explained by upregulation of nitric oxide (NO) synthesis by the vascular endothelium which facilitates vasodilatation induced by adenosine and other NO-dependent dilators and attenuates noradrenaline-evoked vasoconstriction. |
| Databáze: | OpenAIRE |
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