Exchange of oxygen across the epicardial surface distorts estimates of myocardial oxygen consumption

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dc.contributor.author Loiselle, Denis en
dc.date.accessioned 2011-09-06T20:48:03Z en
dc.date.issued 1989 en
dc.identifier.citation J Gen Physiol 94(3):567-590 Sep 1989 en
dc.identifier.issn 0022-1295 en
dc.identifier.uri http://hdl.handle.net/2292/7806 en
dc.description.abstract The rate of oxygen consumption of isolated, Langendorff-circulated, saline-perfused hearts of guinea pigs, rats, and rabbits was measured using the classical Fick Principle method. The heart was suspended in a glass chamber the oxygen partial pressure, PO2, of which could be varied. The measured rate of oxygen consumption was found to vary inversely with the ambient (heart chamber) PO2. This result prevailed whether the chamber was filled with air, saline, or oil, and whether the pericardium was present or the heart was wrapped in Saran. The effect varied inversely with heart size both within and across species. It is concluded that the epicardial surface is permeable to oxygen which will diffuse either into or out of the heart as the PO2 gradient dictates. In either case the classically measured rate of oxygen consumption will be in error. The error can be large in studies of cardiac basal metabolism. A simple model is developed to describe the observed rate of oxygen consumption as classically measured. The measured rate is partitioned into two components: the true rate of oxygen consumption of the heart, and the rate of loss of oxygen by diffusive exchange across the epicardial surface. The latter component is proportional to the gradient of oxygen partial pressure from myocardium to environment and to the diffusive oxygen conductance of myocardial tissue. Application of the model allows the true rate of oxygen consumption of the heart to be recovered from measured values which may be considerably in error. en
dc.language EN en
dc.relation.ispartofseries Journal of General Physiology en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0022-1295/ en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/ en
dc.title Exchange of oxygen across the epicardial surface distorts estimates of myocardial oxygen consumption en
dc.type Journal Article en
pubs.issue 3 en
pubs.begin-page 567 en
pubs.volume 94 (3) en
dc.rights.holder Copyright: The Rockefeller University Press en
dc.identifier.pmid 2607335 en
pubs.end-page 590 en
dc.rights.accessrights http://purl.org/eprint/accessRights/OpenAccess en
pubs.subtype Article en
pubs.elements-id 63191 en
pubs.org-id Bioengineering Institute en
pubs.org-id ABI Associates en
pubs.record-created-at-source-date 2010-09-01 en
pubs.dimensions-id 2607335 en


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