ISSN:
1432-0533
Keywords:
Muscle spindle
;
Electron microscopy
;
Nerve endings
;
Denervation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The nerve endings in muscle spindles from lumbricalis muscles of the hindpaw of the rat were studied by electron microscopy from 10 h to 7 days after section of the sciatic nerve. No sensory endings were found after 5 days and no motor endings after 3 days. Early changes in sensory endings included accumulation of lamellar bodies, mitochondrial swelling or shrinkage, an edematous appearance of the cytoplasm and disruption of membranes. The predominant way of removal was phagocytosis by activated mesenchymal cells; other endings were incorporated into the sarcoplasm as electrondense bodies. Early changes in motor endings included aggregation or swelling of synaptic vesicles, swelling or shrinkage of mitochondria, edematous change of the cytoplasm and disruption of membranes. The predominant way of removal was incorporation into the cytoplasm of adjacent Schwann cells and degradation to phagolysosomes. Sites of removed sensory endings could be identified by basement membrane reduplication, while the intact subsynaptic apparatus of removed motor endings was either loosely covered by Schwann cell processes, or by fibrillar material, or appeared empty. The differences in the removal of motor and sensory endings are explained by the differences in their anatomic structure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00688874
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