Heat-stress relationships of rat cardiac trabeculae determined using a micromechanocalorimeter

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dc.contributor.author Han, June en
dc.contributor.author Taberner, Andrew en
dc.contributor.author Nielsen, Poul en
dc.contributor.author Kirton, Robert en
dc.contributor.author Loiselle, Denis en
dc.contributor.editor Toi, V en
dc.contributor.editor Khoa, TQD en
dc.date.accessioned 2011-11-04T02:05:53Z en
dc.date.issued 2010 en
dc.identifier.citation 3rd International Conference on the Development of Biomedical Engineering in Vietnam, Ho Chi Minh City, Vietnam, 11 Jan 2010 - 14 Jan 2010. Editors: Toi VV, Khoa TQD. IFMBE Proceedings Series. Springer Verlag. 27: 90-93. 2010 en
dc.identifier.isbn 978-3-642-12020-6 en
dc.identifier.issn 1680-0737 en
dc.identifier.uri http://hdl.handle.net/2292/8672 en
dc.description.abstract In order to study the physiology and pathophysiology of the heart, it is insightful to employ isolated cardiac muscle preparations. To that end, we have recently constructed a micromechanocalorimeter for measuring simultaneously the heat rate and force production of superfused cardiac trabeculae. In the microcalorimeter component of the micromechanocalorimeter, two arrays of non-contact thermopile sensors measure the temperature of superfusate upstream and downstream of a centrally-located respiring trabecula. The increment in temperature of superfusate downstream, relative to that upstream, is proportional to the heat liberated by the trabecula. Using the micromechanocalorimeter, we have determined the relationship between heat and force production of rat cardiac trabeculae (n = 10), in 1 mM and 2 mM extracellular calcium concentration ([Ca2+]o) at room temperature (20-22oC). Muscle force was varied by reducing muscle length below optimal value (Lo). Muscle force and rate of heat production were measured simultaneously at two stimulus frequencies: 0.2 Hz and 2.0 Hz. In healthy superfused cardiac trabeculae, we found that heat production was linearly correlated with stress (normalized force) production. The heat-stress regression lines were not significantly different between 0.2 Hz and 2.0 Hz at either value of [Ca2+]. Activation heat values, which are the heat extrapolated to the zero-stress intercepts of the heat-stress regression lines, did not differ between stimulus frequencies, but were significantly higher in 2 mM than in 1 mM [Ca2+]o. We conclude that the heat-stress relationships are independent of stimulus frequency, but dependent on [Ca2+]o. To our knowledge, our micromechanocalorimeter is unique, and has allowed the first determination of the heat-stress relationships of cardiac trabeculae. en
dc.publisher Springer 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. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.subject muscle energetics cardiac trabeculae carneae microcalorimetry en
dc.title Heat-stress relationships of rat cardiac trabeculae determined using a micromechanocalorimeter en
dc.type Conference Item en
dc.identifier.doi 10.1007/978-3-642-12020-6_22 en
pubs.begin-page 90 en
dc.rights.holder Copyright: the author en
pubs.author-url http://dx.doi.org/10.1007/978-3-642-12020-6_22 en
pubs.end-page 93 en
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.elements-id 96571 en
pubs.org-id Bioengineering Institute en
pubs.org-id ABI Associates en
pubs.org-id Engineering en
pubs.org-id Engineering Science en
pubs.org-id Science en
pubs.org-id Science Research en
pubs.org-id Maurice Wilkins Centre (2010-2014) en
pubs.record-created-at-source-date 2010-09-01 en

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