| Effects of alveolar and perfusion hypoxia and hypercapnia on pulmonary vascular resistance in the lamb. | |
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MedLine Citation:
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PMID: 235217 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The effects of ventilatory hypoxia and hypercapnia and perfusion hypoxia and hypercapnia on pulmonary vascular resistance were studied in the intact lamb using right heart techniques to isolate and perfuse the left lower lobe. Ventilatory hypoxia increased vascular resistance in the left lower lobe by constricting predominantly vessels upstream from small lobar veins, presumably small arteries. The response to hypoxia was not blocked by phentolamine and diphenhydramine in doses that markedly decreased pressor responses to norepinephrine and histamine in the lung. Perfusion hypoxia did not alter vascular resistance in the perfused lobe. Ventilatory hypercapnia increased vascular resistance in the lung by constricting mainly upstream vessels, whereas perfusion hypercapnia decreased resistance by dilating upstream vessels. These data indicate that histamine and catecholamines are not involved in the response to alveolar hypoxia. These results suggest that the sensor site for ventilatory hypoxia is close to the alveolus since the response is unrelated to lobar arterial Po2. It is concluded that systemic reflexes are not necessarily involved in the response of the pulmonary vascular bed to ventilatory hypoxia or hypercapnia and that the magnitude and rapidity of this response suggest that it may represent an important local mechanism for the control of ventilation-perfusion relationships in this species. |
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Authors:
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A L Hyman; P J Kadowitz |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 228 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1975 Feb |
Date Detail:
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Created Date: 1975-06-06 Completed Date: 1975-06-06 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 397-403 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Anoxia* Blood Pressure Carbon Dioxide / blood* Diphenhydramine / pharmacology Histamine / pharmacology Hydrogen-Ion Concentration Hypercapnia* Norepinephrine / pharmacology Oxygen / blood* Perfusion Phentolamine / pharmacology Pulmonary Circulation* Sheep Vascular Resistance* |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide; 50-60-2/Phentolamine; 51-41-2/Norepinephrine; 51-45-6/Histamine; 58-73-1/Diphenhydramine; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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