Rapid neuromuscular remodeling following limb immobilization

Wiley - Tập 224 Số 1 - Trang 102-109 - 1989
Mohamed A. Fahim1
1Andrus Gerontology Center and Biological Sciences Department, University of Southern California, Los Angeles, California 90089-0191

Tóm tắt

Abstract

The effect of immobilization on endplate morphology of the rat soleus muscles was studied qualitatively and quantitatively. The endplate was visualized by light microscopic zinc iodide osmium (ZIO) staining and by electron microscopy. The soleus muscle was immobilized by pinning of ankle and knee joints at right angles for 5 days. Immobilized muscles were then compared to the contralateral side and to normal litter mates. After 5 days of partial disuse, muscle fibers atrophied and nerve terminal area increased in ZIO‐determined measurements. Neuromuscular junctions (NMJs) of disuse muscle fibers visualized by electron microscopy exhibited greater amounts of degeneration than either contralateral or control NMJs. Degeneration consisted of nerve terminal disruption, exposed junctional folds, and postsynaptic areas which contained little or no postjunctional folds. Regeneration also occurred in the same NMJs, consisting of small terminals associated with large expansion of junctional folds, several small terminals occurring within the same primary synaptic cleft, and several axons wrapped by the same Schwann cell. These observations demonstrate, for the first time, that partial disuse for only 5 days produces muscle atrophy as well as denervation‐like changes at the NMJ, which leads to terminal sprouting within the endplate area and remodelling.

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Tài liệu tham khảo

10.1016/0006-8993(68)90104-2

10.1007/BF01637652

10.1152/jappl.1979.47.5.974

10.1146/annurev.ne.04.030181.000313

10.1038/275652a0

10.1016/0006-8993(82)90599-6

10.1038/265459a0

10.1002/ar.1092070303

10.1002/mus.880100303

10.1113/jphysiol.1981.sp013680

10.1007/BF01262429

10.1016/0006-8993(86)90039-9

10.1113/jphysiol.1969.sp008757

10.1016/0301-0082(81)90006-X

10.1016/0306-4522(81)90055-5

10.1016/0306-4522(86)90069-2

10.1016/0306-4522(84)90207-0

Lomo T., 1976, Motor Innervation of Muscle, 289

10.1152/jappl.1977.43.4.700

Nudell B. M., 1983, Regulation of synaptic position, size, and strength in anuran skeletal muscle, J. Neurosci., 3, 161, 10.1523/JNEUROSCI.03-01-00161.1983

10.1007/BF01148599

10.1126/science.204007

10.1016/0166-2236(80)90045-4

10.1007/BF01224810

Robbins N., 1971, Effect of chronic disuse of rat soleus neuromuscular junctions on presynaptic function, J. Neurophysiol., 34, 570, 10.1152/jn.1971.34.4.570

Santa T., 1973, New Developments in Electromyography and Clinical Neurophysiology, 41

10.1152/ajpcell.1982.242.1.C12

10.1038/281069a0

10.1016/0014-4886(82)90104-2

10.1097/00005072-197703000-00004

Tucker K. R., 1981, Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization, J. Appl. Physiol., 51, 73, 10.1152/jappl.1981.51.1.73

10.1007/BF01181538