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Cardiac beta-adrenergic receptors and coronary hemodynamics in the conscious dog during hypoxic hypoxia.The mechanisms by which acute hypoxia (10% and 5% oxygen) mediates changes in coronary blood flow and cardiac function were investigated in the conscious dog. When the dogs breathed hypoxic gas mixtures through a tracheostomy, both arterial and coronary sinus oxygen tensions were significantly decreased. With 5% oxygen, there were significant increases in heart rate (25%), maximum left ventricular dP/dt (39%), left circumflex coronary artery blood flow (163%), and left ventricular oxygen consumption (52%), which were attenuated by beta-adrenergic blockage with propranolol. When electrical pacing was used to keep the ventricular rate constant during hypoxia, there was no significant difference in coronary blood flow before and after beta blockade. Beta-adrenergic receptor activity in the myocardium participates in the integrated response to hypoxia although it may not cause active vasodilation of the coronary vessels.
Document ID
19720043816
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Erickson, H. H.
Stone, H. L.
(USAF, School of Aerospace Medicine, Brooks AFB Tex., United States)
Date Acquired
August 6, 2013
Publication Date
April 1, 1972
Publication Information
Publication: Aerospace Medicine
Volume: 43
Subject Category
Biosciences
Accession Number
72A27482
Distribution Limits
Public
Copyright
Other

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