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The dose‐related response of rabbit fast muscle to long‐term low‐frequency stimulation
Author(s) -
Sutherland Hazel,
Jarvis Jonathan C.,
Kwende Martin M. N.,
Gilroy Stephen J.,
Salmons Stanley
Publication year - 1998
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/(sici)1097-4598(199812)21:12<1632::aid-mus3>3.0.co;2-w
Subject(s) - myosin , stimulation , contraction (grammar) , gene isoform , muscle contraction , medicine , endocrinology , skeletal muscle , oxidative phosphorylation , chemistry , biology , biochemistry , gene
Rabbit tibialis anterior muscles were stimulated continuously at 2.5 Hz, 5 Hz, or 10 Hz for 10 months. The resulting adaptive transformation was dose‐related for contractile speed, myosin isoform composition, and enzyme activities. The “fast‐oxidative” state produced by stimulation at 2.5 Hz was stable: even after 10 months, 84% of the fibers were of type 2A. Absence of a secondary decline in oxidative activity in these muscles provided strong evidence of a causal link between myosin transitions and metabolic adaptation. Significant fiber loss occurred only after prolonged stimulation at 10 Hz. The myosin isoform composition of individual muscles stimulated at 5 Hz resembled that of muscles stimulated at either the lower or the higher frequency, behavior consistent with a threshold for fiber type change. In clinical applications such as cardiomyoplasty, muscles could be used more effectively by engineering their properties to combine speed and power of contraction with the necessary resistance to fatigue. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1632–1646, 1998