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Alterations of intrinsic tongue muscle properties with aging
Author(s) -
Cullins Miranda J.,
Connor Nadine P.
Publication year - 2017
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.25605
Subject(s) - isometric exercise , swallowing , tongue , myosin , anatomy , fiber , muscle fibre , fiber type , age groups , biology , medicine , chemistry , physiology , biophysics , skeletal muscle , pathology , surgery , demography , organic chemistry , sociology
: Age‐related decline in the intrinsic lingual musculature could contribute to swallowing disorders, yet the effects of age on these muscles is unknown. We hypothesized there is reduced muscle fiber size and shifts to slower myosin heavy chain (MyHC) fiber types with age. Methods : Intrinsic lingual muscles were sampled from 8 young adult (9 months) and 8 old (32 months) Fischer 344/Brown Norway rats. Fiber size and MyHC were determined by fluorescent immunohistochemistry. Results : Age was associated with a reduced number of rapidly contracting muscle fibers, and more slowly contracting fibers. Decreased fiber size was found only in the transverse and verticalis muscles. Discussion : Shifts in muscle composition from faster to slower MyHC fiber types may contribute to age‐related changes in swallowing duration. Decreasing muscle fiber size in the protrusive transverse and verticalis muscles may contribute to reductions in maximum isometric tongue pressure found with age. Differences among regions and muscles may be associated with different functional demands. Muscle Nerve 56 : E119–E125, 2017