title: Force produced after stretch in sarcomeres and half-sarcomeres isolated from skeletal muscles.
abstract: The goal of this study was to evaluate if isolated sarcomeres and half-sarcomeres produce a long-lasting increase in force after a stretch is imposed during activation. Single and half-sarcomeres were isolated from myofibrils using micro-needles, which were also used for force measurements. After full force development, both preparations were stretched by different magnitudes. The sarcomere length (SL) or half-sarcomere length variations (HSL) were extracted by measuring the initial and final distances from the Z-line to the adjacent Z-line or to a region externally adjacent to the M-line of the sarcomere, respectively. Half-sarcomeres generated approximately the same amount of isometric force (29.0 ± SD 15.5 nN·μm(-2)) as single sarcomeres (32.1 ± SD 15.3 nN·μm(-2)) when activated. In both cases, the steady-state forces after stretch were higher than the forces during isometric contractions at similar conditions. The results suggest that stretch-induced force enhancement is partly caused by proteins within the half-sarcomere.
authors.affiliation: Department of Kinesiology and Physical Education, McGill University, Canada.
authors.forename: Fábio C
authors.initials: FC
authors.lastname: Minozzo
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Baroni
authors.forename: José A
authors.initials: JA
authors.lastname: Correa
authors.forename: Marco A
authors.initials: MA
authors.lastname: Vaz
authors.forename: Dilson E
authors.initials: DE
authors.lastname: Rassier
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D055119:Elastic Modulus / Q000502:physiology; D007537:Isometric Contraction / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods*; D011817:Rabbits; D012518:Sarcomeres / Q000502:physiology* / Q000648:ultrastructure*; D013314:Stress, Mechanical
references.citation: Pflugers Arch. 2009 Apr;457(6):1415-22
references.pmid: 19104827
references.citation: J Biomech. 2009 Dec 11;42(16):2808-12
references.pmid: 19765710
references.citation: J Physiol. 1992;451:503-23
references.pmid: 1403822
references.citation: Am J Physiol Cell Physiol. 2012 Jan 1;302(1):C240-8
references.pmid: 21998143
references.citation: Biophys J. 1990 Feb;57(2):209-21
references.pmid: 2317547
references.citation: Am J Physiol Cell Physiol. 2010 Nov;299(5):C1127-35
references.pmid: 20720178
references.citation: Proc Biol Sci. 2008 Nov 22;275(1651):2577-86
references.pmid: 18664437
references.citation: Exp Physiol. 1994 Sep;79(5):831-8
references.pmid: 7818869
references.citation: J Muscle Res Cell Motil. 1993 Oct;14(5):498-510
references.pmid: 8300845
references.citation: Biophys J. 2010 Jun 2;98(11):2582-90
references.pmid: 20513402
references.citation: J Physiol. 2006 May 15;573(Pt 1):173-85
references.pmid: 16527855
references.citation: Am J Physiol Cell Physiol. 2009 Nov;297(5):C1211-9
references.pmid: 19710362
references.citation: Am J Physiol Cell Physiol. 2010 Jul;299(1):C14-20
references.pmid: 20357181
references.citation: Proc Biol Sci. 2010 Feb 7;277(1680):475-84
references.pmid: 19846455
references.citation: Am J Physiol Cell Physiol. 2012 Feb 1;302(3):C566-74
references.pmid: 22094333
references.citation: Proc Natl Acad Sci U S A. 2003 Nov 11;100(23):13716-21
references.pmid: 14593205
references.citation: J Physiol. 1979 Aug;293:379-92
references.pmid: 315465
references.citation: Biophys J. 2006 Jan 15;90(2):514-30
references.pmid: 16239326
references.citation: J Struct Biol. 2005 Aug;151(2):182-95
references.pmid: 16043363
references.citation: J Physiol. 1966 May;184(1):170-92
references.pmid: 5921536
references.citation: PLoS Comput Biol. 2011 Sep;7(9):e1002156
references.pmid: 21980268
references.citation: Am J Physiol Regul Integr Comp Physiol. 2007 Mar;292(3):R1129-36
references.pmid: 17082350
references.citation: J Physiol. 1952 May;117(1):77-86
references.pmid: 14946730
references.citation: Proc Biol Sci. 2003 Aug 22;270(1525):1735-40
references.pmid: 12965002
references.citation: PLoS One. 2012;7(1):e29356
references.pmid: 22242168
references.citation: Biophys J. 1994 Jul;67(1):283-92
references.pmid: 7918996