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dc.contributor.authorWiden, Cecilia
dc.contributor.authorBarclay, Chris
dc.date.accessioned2017-05-03T11:39:53Z
dc.date.available2017-05-03T11:39:53Z
dc.date.issued2006
dc.date.modified2008-11-10T07:10:32Z
dc.identifier.issn00223751
dc.identifier.doi10.1113/jphysiol.2006.104992
dc.identifier.urihttp://hdl.handle.net/10072/14253
dc.description.abstractThe aim of this study was to quantify the fraction of cross-bridges that cycle during a cardiac twitch. Measurements of the energetics of contracting left ventricular mouse papillary muscle were made in vitro (27C) using the myothermic technique. Enthalpy output was partitioned into force-dependent and force-independent components using 2,3-butanedione monoxime (BDM) to selectively inhibit cross-bridge cycling. For isometric contractions and a contraction frequency of 2 Hz the net enthalpy output was 5.7 ᰮ8 mJ/g/twitch and initial enthalpy output was 2.3 ᰮ3 mJ/g/twitch (n =11). Assuming that low concentrations of BDM did not affect Ca2+ cycling, force-independent enthalpy output was 18.6 ᱮ9% (n =7) of the initial enthalpy output. Enthalpy output decreased with increased contraction frequency but was independent of shortening velocity. On the basis of these values, it was calculated that the twitch energetics were consistent with ATP splitting by half the cross-bridges and the pumping of one Ca2+ into the sarcoplasmic reticulum for every three cross-bridge cycles. The simplest interpretation is that half the cross-bridges completed one ATP-splitting cycle in each twitch. The lack of influence of shortening velocity on energy cost supports the idea that the amount of energy to be used is determined early in a twitch and is not greatly influenced by events that occur during the contraction.
dc.description.peerreviewedYes
dc.description.publicationstatusYes
dc.languageEnglish
dc.language.isoeng
dc.publisherBlackwell Publishing Ltd
dc.publisher.placeOxford, UK
dc.publisher.urihttps://physoc.onlinelibrary.wiley.com/toc/14697793/2006/573/1
dc.relation.ispartofstudentpublicationY
dc.relation.ispartofpagefrom5
dc.relation.ispartofpageto15
dc.relation.ispartofissue1
dc.relation.ispartofjournalThe Journal of Physiology
dc.relation.ispartofvolume573
dc.rights.retentionN
dc.subject.fieldofresearchBiological Sciences
dc.subject.fieldofresearchMedical and Health Sciences
dc.subject.fieldofresearchcode06
dc.subject.fieldofresearchcode11
dc.titleATP splitting by half the cross-bridges can explain the twitch energetics of mouse papillary muscle
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
gro.facultyGriffith Health, School of Allied Health Sciences
gro.date.issued2006
gro.hasfulltextNo Full Text
gro.griffith.authorBarclay, Chris
gro.griffith.authorWiden, Cecilia


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