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Association between biochemical and physiological properties in single motor units
Author(s) -
Hamm Thomas M.,
Nemeth Patti M.,
Solanki Lata,
Gordon Debra A.,
Reinking Robert M.,
Stuart Douglas G.
Publication year - 1988
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880110309
Subject(s) - lactate dehydrogenase , motor unit , succinic dehydrogenase , succinate dehydrogenase , biology , glycogen , malate dehydrogenase , anatomy , biochemistry , enzyme
Motor units from the cat tibialis posterior muscle were examined for an association between physiological and biochemical properties. Functionally isolated motor units were categorized on the basis of their physiological properties. This was followed by quantitative microbiochemical analysis of single muscle fibers from each unit, identified in cross sections using the glycogen‐depletion method. The activities of malate dehydrogenase and β;‐hydroxyacyl‐CoA dehydrogenase distinguished between fatigable (type FF) and fatigue‐resistant (types FR and S) units. The activities of both lactate dehydrogenase and adenylokinase were higher in fast‐than in slow‐contracting units. Cluster analyses, based on both physiological and biochemical properties alone, produced groupings identical to types FF, FR, and S. The association between physiological and biochemical properties substantiates the idea that biochemically distinct groups of motor units correspond to physiologically identifiable groups.