Generation of tension by skinned fibers and intact skeletal muscles from desmin-deficient mice.
We have investigated the physiological role of desmin in skeletal muscle by measuring isometric tension generated in skinned fibres and intact skeletal muscles from desmin knock-out (DES-KO) mice. About 80% of skinned single extensor digitorum longus (EDL) fibres from adult DES-KO mice generated tensions close to that of wild-type (WT) controls. Weights and maximum tensions of intact EDL but not of soleus (SOL) muscles were lowered in DES-KO mice. Repeated contractions with stretch did not affect subsequent isometric tension in EDL muscles of DES-KO mice. Tension during high frequency fatigue (HFF) declined faster and this deficiency was compensated in DES-KO EDL muscles by 5 mM caffeine which had no influence on HFF in WT EDL. Furthermore, caffeine evoked twitch potentiation was higher in DES-KO than in WT muscles. We conclude that desmin is not essential for acute tensile strength but rather for optimal activation of intact myofibres during E-C coupling.
Wieneke
S
S
Developmental Biology Unit, University of Bielefeld, Bielefeld, D-33501, Germany.
Stehle
R
R
Li
Z
Z
Jockusch
H
H
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D003893:Desmin / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D009929:Organ Size; D010641:Phenotype
D003893:Desmin; D002110:Caffeine