In:
American Journal of Physiology-Legacy Content, American Physiological Society, Vol. 185, No. 2 ( 1956-05-01), p. 287-298
Abstract:
Skeletal muscle, which has been histochemically characterized by: a) extracellular tissue comprising extracellular fluid plus connective tissue solids, and b) intracellular tissue comprising intracellular water and fiber solids, has provided a method to interpret quantitatively what occurs when skeletal muscle atrophies. Histochemical findings from skeletal muscle (calf and thigh groups) from the legs of puppies following disuse brought about by denervation were compared with those obtained on muscles removed from the opposite weight-bearing leg, the control leg. All tissue data were calculated on a fat-free basis. The calculation of the extracellular tissue mass was based on the chloride space, and the estimation of the connective tissue solids was based on the collagen nitrogen values. The histochemical interpretations indicated that following the denervation of muscle the change of greatest magnitude was in the mass of the extracellular tissue. In a kilogram of control calf muscle the extracellular mass (F) was 295 gm, of which 47 gm were the connective tissue solids. In a kilogram of denervated calf muscle the (F) was 397 gm, of which 57 gm were connective tissue solids. In a kilogram of control thigh muscles the (F) was 249 gm containing 41 gm of connective tissue solids; and there were 378 gm in the (F) of the denervated thigh containing 52 gm of connective tissue solids. After correcting the determined total solids of the muscles for the connective tissue solids, the remaining solids were allotted to the muscle fiber solids. Therefore in atrophied muscle there was a decrease in the muscle fiber solids of 166 gm (control) to 137 gm (denervated). Since histologically a definite shortening of fibers has been found, the histochemical decrease in the fiber weight must be the result of shortening of the muscle fibers. Histochemical evidence that the internal structure of the muscle fibers did not change in denervation was provided by the findings that the calculated concentrations of potassium (156 mEq) and magnesium (30 mEq)/kg of muscle fiber water did not differ from the control values. Likewise, the amount of water per kilogram of muscle fibers remained the same: 77% in the control and denervated calf muscles, and 78% in all of the thigh muscles.
Type of Medium:
Online Resource
ISSN:
0002-9513
DOI:
10.1152/ajplegacy.1956.185.2.287
Language:
English
Publisher:
American Physiological Society
Publication Date:
1956
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12
