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Muscle fiber type correlates with innervation topography in the rat serratus anterior muscle
Author(s) -
Grow Wade A.,
KendallWassmuth Eydie,
Grober Matthew S.,
Ulibarri Catherine,
Laskowski Michael B.
Publication year - 1996
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(199605)19:5<605::aid-mus8>3.0.co;2-f
Subject(s) - anatomy , fiber type , muscle fibre , medicine , biology , skeletal muscle
Previous studies have reported that motoneurons from the sixth spinal nerve (C6) innervate the majority of muscle fibers in the rat serratus anterior (SA) muscle. The seventh spinal nerve (C7) innervates a limited number of SA fibers, increasing caudally. This topographic map is partially reestablished following denervation. In the present study, muscle fibers of the SA were stained with monoclonal antibodies for the muscle‐specific fast myosin heavy chain (F‐MHC) and slow myosin heavy chain (S‐MHC) proteins. We found that the majority of fibers in the SA muscle stained for F‐MHC antibody, and the percentage of muscle fibers staining for S‐MHC antibody increased caudally. When newborn SA muscles were denervated and then reinnervated by the entire long thoracic (LT) nerve or only the C6 branch to the LT nerve, the reinnervated muscle had the normal proportion of muscle fibers expressing S‐MHC protein. However, if the LT nerve was crushed and only C7 motoneurons allowed to reinnervate the SA muscle, a greater percentage of muscle fibers stained for S‐MHC antibody than normal. We conclude that there is a correlation between muscle fiber type and innervation topography in the SA muscle of the rat. © 1996 John Wiley & Sons, Inc.