title: α1-Syntrophin-deficient mice exhibit impaired muscle force recovery after osmotic shock.
abstract: BACKGROUND
  α1-syntrophin, a member of the dystrophin complex, recruits membrane molecules, including aquaporin-4, at the sarcolemma. The physiological functions of α1-syntrophin are poorly understood.
  
  
  METHODS
  We examined the physiological characteristics of α1-syntrophin-deficient muscles under osmotic stress conditions to test the possibility that mutant muscles are less tolerant of osmotic shock.
  
  
  RESULTS
  Isolated muscle bundles from mutant mice showed markedly reduced force production after hypo-osmotic shock. In addition, the mutant muscle bundles showed delayed recovery of specific gravity after being exposed to hypo-osmotic conditions. Two consecutive exercise tests on the treadmill revealed their performance in the second test was significantly lower than for wild-type mice. Furthermore, mutant mice had higher serum lactate concentrations after treadmill exercise.
  
  
  CONCLUSIONS
  Although the lack of α1-syntrophin from the sarcolemma does not lead to muscle degeneration, our results suggest that it may be partly involved in the pathophysiology of dystrophin-deficient Duchenne muscular dystrophy.
authors.affiliation: Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-higashi, Kodaira, Tokyo, 187-8502, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Yokota
authors.forename: Yuko
authors.initials: Y
authors.lastname: Miyagoe-Suzuki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ikemoto
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Matsuda
authors.forename: Shin'ichi
authors.initials: S
authors.lastname: Takeda
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004195:Disease Models, Animal; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000097:blood; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D018763:Muscle Fatigue / Q000235:genetics* / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000502:physiology*; D009124:Muscle Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D053580:Muscle Strength / Q000235:genetics / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology*; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000503:physiopathology*; D009997:Osmotic Pressure / Q000502:physiology*
chemical_list: D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; C091825:syntrophin alpha1; D019344:Lactic Acid
keywords: Duchenne muscular dystrophy; aquaporin-4; fatigue; osmotic regulation; α1-syntrophin