title: High temperature does not alter fatigability in intact mouse skeletal muscle fibres.
abstract: Intense activation of skeletal muscle results in fatigue development, which involves impaired function of the muscle cells resulting in weaker and slower contractions. Intense muscle activity also results in increased heat production and muscle temperature may rise by up to 6 degrees C. Hyperthermia is associated with impaired exercise performance in vivo and recent studies have shown contractile dysfunction and premature fatigue development in easily fatigued muscle fibres stimulated at high temperatures and these defects were attributed to oxidative stress. Here we studied whether fatigue-resistant soleus fibres stimulated at increased temperature show premature fatigue development and whether increasing the level of oxidative stress accelerates fatigue development. Intact single fibres or small bundles of soleus fibres were fatigued by 600 ms tetani given at 2 s intervals at 37 degrees C and 43 degrees C, which is the highest temperature the muscle would experience in vivo. Tetanic force in the unfatigued state was not significantly different at the two temperatures. With 100 fatiguing tetani, force decreased by approximately 15% at both temperatures; the free cytosolic [Ca(2+)] (assessed with indo-1) showed a similar approximately 10% decrease at both temperatures. The oxidative stress during fatigue at 43 degrees C was increased by application of 10 microM hydrogen peroxide or tert-butyl hydroperoxide and this did not cause premature fatigue development. In summary, fatigue-resistant muscle fibres do not display impaired contractility and fatigue resistance at the highest temperature that mammals, including humans, would experience in vivo. Thus, intrinsic defects in fatigue-resistant muscle fibres cannot explain the decreased physical performance at high temperatures.
authors.affiliation: Department of Physiology and Pharmacology, Karolinska Institute, Stockholm S-171 77, Sweden.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Place
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamada
authors.forename: Shi-Jin
authors.initials: SJ
authors.lastname: Zhang
authors.forename: Håkan
authors.initials: H
authors.lastname: Westerblad
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Bruton
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D004558:Electric Stimulation; D015444:Exercise / Q000502:physiology; D005334:Fever / Q000503:physiopathology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology*; D018384:Oxidative Stress; D013696:Temperature; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
chemical_list: D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D002118:Calcium
references.citation: Acta Physiol Scand. 2005 Feb;183(2):181-90
references.pmid: 15676059
references.citation: Physiol Rev. 2008 Oct;88(4):1243-76
references.pmid: 18923182
references.citation: Am J Physiol Cell Physiol. 2000 Oct;279(4):C1058-66
references.pmid: 11003586
references.citation: J Physiol. 2008 Aug 15;586(16):3979-90
references.pmid: 18591188
references.citation: Am J Physiol Cell Physiol. 2007 Aug;293(2):C650-60
references.pmid: 17459949
references.citation: Am J Physiol Regul Integr Comp Physiol. 2004 Oct;287(4):R698-705
references.pmid: 15178539
references.citation: J Physiol. 1958 Oct 31;143(3):454-73
references.pmid: 13588567
references.citation: J Appl Physiol. 1972 May;32(5):635-43
references.pmid: 5038852
references.citation: FASEB J. 2001 Feb;15(2):309-11
references.pmid: 11156946
references.citation: J Physiol. 2003 Nov 1;552(Pt 3):833-44
references.pmid: 12937290
references.citation: J Physiol. 2006 Apr 15;572(Pt 2):551-9
references.pmid: 16455685
references.citation: Am J Physiol. 1971 Aug;221(2):427-31
references.pmid: 5560291
references.citation: J Muscle Res Cell Motil. 2005;26(4-5):225-35
references.pmid: 16322911
references.citation: J Physiol. 2001 Nov 1;536(Pt 3):879-91
references.pmid: 11691880
references.citation: Am J Physiol. 1985 Mar;248(3 Pt 1):C265-70
references.pmid: 3976876
references.citation: J Physiol. 2002 Nov 1;544(3):765-76
references.pmid: 12411522
references.citation: Pflugers Arch. 1993 Sep;424(5-6):478-87
references.pmid: 8255731
references.citation: J Appl Physiol (1985). 2008 Mar;104(3):871-8
references.pmid: 17962572
references.citation: J Appl Physiol (1985). 1998 Aug;85(2):478-83
references.pmid: 9688723
references.citation: J Physiol. 2005 Apr 1;564(Pt 1):189-99
references.pmid: 15718257
references.citation: Exp Physiol. 1995 Jul;80(4):497-527
references.pmid: 7576593
references.citation: J Physiol. 2005 Mar 1;563(Pt 2):621-31
references.pmid: 15613373
references.citation: J Appl Physiol (1985). 2008 Jan;104(1):296-305
references.pmid: 17962573
references.citation: J Appl Physiol (1985). 2009 Feb;106(2):378-84
references.pmid: 19057001
references.citation: Nature. 1985 Mar 14-20;314(6007):164-6
references.pmid: 3974720
references.citation: J Physiol. 2006 Feb 15;571(Pt 1):191-200
references.pmid: 16339177
references.citation: J Appl Physiol (1985). 1999 Mar;86(3):1032-9
references.pmid: 10066720
references.citation: Proc Natl Acad Sci U S A. 2009 May 26;106(21):8665-70
references.pmid: 19433800
references.citation: Muscle Nerve. 1987 Jun;10(5):439-45
references.pmid: 3614258
references.citation: J Physiol. 2007 Jul 15;582(Pt 2):843-57
references.pmid: 17510189
references.citation: Am J Physiol Cell Physiol. 2006 Jul;291(1):C147-54
references.pmid: 16481370
references.citation: Am J Physiol Regul Integr Comp Physiol. 2008 Nov;295(5):R1695-705
references.pmid: 18768765
references.citation: Physiol Rev. 2008 Jan;88(1):287-332
references.pmid: 18195089
references.citation: J Biol Chem. 1985 Mar 25;260(6):3440-50
references.pmid: 3838314
references.citation: J Physiol. 2009 Oct 1;587(Pt 19):4705-16
references.pmid: 19470779
references.citation: J Physiol. 1995 Aug 1;486 ( Pt 3):689-94
references.pmid: 7473229
references.citation: J Appl Physiol (1985). 2001 Sep;91(3):1055-60
references.pmid: 11509498
references.citation: Am J Respir Crit Care Med. 1997 Jul;156(1):140-5
references.pmid: 9230738
references.citation: J Physiol. 2003 Aug 15;551(Pt 1):179-90
references.pmid: 12815178
references.citation: J Neurophysiol. 2007 Jan;97(1):596-603
references.pmid: 17093121
references.citation: J Physiol. 1998 Jun 1;509 ( Pt 2):565-75
references.pmid: 9575304
references.citation: J Physiol. 1997 Apr 1;500 ( Pt 1):193-204
references.pmid: 9097943