Development and use of the incremental twitch subtraction MUNE method in mice.
We have used a technique to estimate the number of functioning motor units (MUNE) innervating a muscle in mice based on twitch tension. The MUNE technique was verified by modeling twitch tensions from isolated ventral root stimulation. Analysis by twitch tensions allowed us to identify motor unit fiber types. The MUNE technique was used to compare normal mice with transgenic superoxide dismutase-1 mutation (G94A) mice to assess the time course of motor unit loss with respect to fiber type. Motor unit loss was found to occur well in advance of behavioral changes and the degree of reinnervation is dependent upon motor unit fiber types.
Hegedus
Janka
J
Division of Physical Medicine and Rehabilitation, Faculty of Medicine and Dentistry, 525, Heritage Medical Research Center, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
Jones
Kelvin E
KE
Gordon
Tessa
T
D000200:Action Potentials / Q000235:genetics / Q000502:physiology*; D000409:Alanine / Q000235:genetics; D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology* / Q000503:physiopathology*; D000818:Animals; D001703:Biophysics; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D007537:Isometric Contraction / Q000502:physiology; D008239:Lysine / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology; D009154:Mutation / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics; D000072105:Superoxide Dismutase-1; D013997:Time Factors
C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D008239:Lysine; D000409:Alanine