HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 286/2/H708    most recent 00580.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Kirton, R. S. Articles by Loiselle, D. S. Search for Related Content PubMed PubMed Citation Articles by Kirton, R. S. Articles by Loiselle, D. S.

Strain softening is not present during axial extensions of rat intact right ventricular trabeculae in the presence or absence of 2,3-butanedione monoxime

¹Bioengineering Institute and Departments of ²Anatomy, ³Engineering Science, and ⁴Physiology, The University of Auckland, Auckland 1001, New Zealand; and ⁵Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307

Submitted 23 June 2003 ; accepted in final form 2 October 2003

Recent studies of passive myocardial mechanics have shown that strain softening behavior is present during both inflation of isolated whole rat hearts and shearing of tissue blocks taken from the left ventricular free wall in pigs. Strain softening is typically manifested by a stiffer forceextension relation in the first deformation cycle relative to subsequent cycles and is distinguished from viscoelasticity by a lack of recovery of stiffness, even after several hours of rest. The causes of this behaviour are unknown. We investigated whether strain softening is observed in uniaxial extensions of intact, viable, rat right ventricular (RV) cardiac trabeculae. Stretch and release cycles of 5%, 10%, and 15% muscle length were applied at a constant velocity at 26°C. Muscles were tested in random order in the presence and absence of 50 mM 2,3-butanedione monoxime (BDM). Whereas strain softening was displayed by nonviable trabeculae, it was not observed in viable preparations undergoing physiologically relevant extensions whether in the presence or absence of BDM. BDM also had no effect on passive compliance. There was a reversible increase of muscle compliance between the first and subsequent cycles, with recovery after 30 s of rest, independent of the presence of BDM. We conclude that strain softening is neither intrinsic to viable rat RV trabeculae nor influenced by BDM and that passive trabeculae compliance is not altered by the addition of BDM.

cardiac muscle; passive tissue compliance; stress-strain relations; stretch

This article has been cited by other articles:

				C. F. Asnes, J. P. Marquez, E. L. Elson, and T. Wakatsuki Reconstitution of the Frank-Starling Mechanism in Engineered Heart Tissues Biophys. J., September 1, 2006; 91(5): 1800 - 1810. [Abstract] [Full Text] [PDF]

				J. E. Speich, L. Borgsmiller, C. Call, R. Mohr, and P. H. Ratz ROK-induced cross-link formation stiffens passive muscle: reversible strain-induced stress softening in rabbit detrusor Am J Physiol Cell Physiol, July 1, 2005; 289(1): C12 - C21. [Abstract] [Full Text] [PDF]

				R. S. Kirton, A. J. Taberner, P. M. F. Nielsen, A. A. Young, and D. S. Loiselle Effects of BDM, [Ca2+]o, and temperature on the dynamic stiffness of quiescent cardiac trabeculae from rat Am J Physiol Heart Circ Physiol, April 1, 2005; 288(4): H1662 - H1667. [Abstract] [Full Text] [PDF]