title: Lower active force generation and improved fatigue resistance in skeletal muscle from desmin deficient mice.
abstract: The mechanical effects of the intermediate filament protein desmin was examined in desmin deficient mice (Des-/-) and their wild type control (Des+/+). Active force generation was determined in intact soleus muscles and in skinned single fibres from soleus and psoas. A decreased force generation of skinned muscle fibres from Des-/- mice and a tendency towards decreased active force in intact soleus muscle were detected. Concentrations of the contractile protein actin and myosin were not altered in Des-/- muscles. Ca(2+)-sensitivity of skinned single fibres in Des-/- muscles was unchanged compared to Des+/+. Using a protocol with repeated short tetani an increased fatigue resistance was found in the intact soleus muscles from Des-/- mice. In conclusion, desmin intermediate filaments are required for optimal generation or transmission of active force in skeletal muscle. Although other studies have shown that the desmin intermediate filaments appear to influence Ca(2+)-handling, the Ca(2+)-sensitivity of the contractile filaments is not altered in skeletal muscle of Des-/- mice. Previous studies have reported a switch towards slower myosin isoforms in slow skeletal muscle of Des-/- mice. The increased fatigue resistance show that this change is reflected in the physiological function of the muscle.
authors.affiliation: Department of Physiological Sciences, Lund University, BMC F11, Tornavägen 10, SE-221 84, Lund, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Balogh
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: D
authors.initials: D
authors.lastname: Paulin
authors.forename: A
authors.initials: A
authors.lastname: Arner
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003893:Desmin / Q000172:deficiency / Q000235:genetics*; D004558:Electric Stimulation; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000378:metabolism / Q000502:physiology*; D009218:Myosins / Q000378:metabolism; D016658:Psoas Muscles / Q000294:innervation / Q000378:metabolism / Q000502:physiology*
chemical_list: D000199:Actins; D003893:Desmin; D009218:Myosins; D002118:Calcium