Document Detail


Catecholamine-induced opening of intrapulmonary arteriovenous anastomoses in healthy humans at rest.
MedLine Citation:
PMID:  22858627     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The mechanism or mechanisms that cause intrapulmonary arteriovenous anastomoses (IPAVA) to either open during exercise in subjects breathing room air and at rest when breathing hypoxic gas mixtures, or to close during exercise while breathing 100% oxygen, remain unknown. During conditions when IPAVA are open, plasma epinephrine (EPI) and dopamine (DA) concentrations both increase, potentially representing a common mechanism. The purpose of this study was to determine whether EPI or DA infusions open IPAVA in resting subjects breathing room air and, subsequently, 100% oxygen. We hypothesized that these catecholamine infusions would open IPAVA. We performed saline-contrast echocardiography in nine subjects without a patent foramen ovale before and during serial EPI and DA infusions while breathing room air and then while breathing 100% oxygen. Bubble scores (0-5) were assigned based on the number and spatial distribution of bubbles in the left ventricle. Pulmonary artery systolic pressure (PASP) was estimated using Doppler ultrasound, while cardiac output (Q(C)) was measured using echocardiography. Bubble scores were significantly greater during EPI infusions of 80-320 ng·kg(-1)·min(-1) compared with baseline when subjects breathed room air; however, bubble scores did not increase when they breathed 100% oxygen. At comparable Q(C) and PASP, intravenous DA (16 μg·kg(-1)·min(-1)) and EPI (40 ng·kg(-1)·min(-1)) resulted in identical bubble scores. Subsequent studies revealed that β-blockade did not prevent hypoxia-induced opening of IPAVA. We suggest that increases in Q(C) or PASP (or both) secondary to EPI or DA infusions open IPAVA in normoxia. The closing mechanism associated with breathing 100% oxygen is independent from the opening mechanisms.
Authors:
Steven S Laurie; Jonathan E Elliott; Randall D Goodman; Andrew T Lovering
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-08-02
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  113     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-16     Completed Date:  2013-06-17     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1213-22     Citation Subset:  IM    
Affiliation:
Department of Human Physiology, University of Oregon, Eugene, OR 97403, USA.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / pharmacology
Adult
Anoxia / metabolism,  physiopathology,  ultrasonography
Arterial Pressure / drug effects,  physiology
Arteriovenous Anastomosis / drug effects*,  metabolism,  physiology*,  ultrasonography
Cardiac Output / drug effects,  physiology
Catecholamines / pharmacology*
Dopamine / pharmacology
Echocardiography / methods
Epinephrine / pharmacology
Exercise / physiology*
Exercise Test / methods
Female
Foramen Ovale, Patent / metabolism,  physiopathology,  ultrasonography
Heart Ventricles / drug effects,  metabolism,  physiopathology,  ultrasonography
Humans
Male
Oxygen / metabolism
Pulmonary Artery / drug effects,  metabolism,  physiology,  ultrasonography
Pulmonary Circulation / drug effects,  physiology
Pulmonary Gas Exchange / drug effects,  physiology
Rest / physiology*
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 0/Catecholamines; 51-43-4/Epinephrine; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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