Title: An electron microscopic study of the changes induced by botulinum toxin in the motor end-plates of slow and fast skeletal muscle fibres of the mouse
Abstract: An electron microscopic study was made of the motor innervation of slow (soleus) and fast (superficial gastrocnemius) skeletal muscle fibres of the mouse after a single local injection of a sublethal quantity of botulinum toxin. The muscles became paralysed within 24 hr of the injection and recovered only after several weeks. Sprouting from nerve terminals in motor end-plates was seen in soleus at 4 days but in gastrocnemius nerve sprouts were found only after about 4 weeks. Nerve sprouts were always enclosed in processes of Schwann cells. New nerve-muscle contacts were formed and were at first loose and irregularly interrupted by Schwann cell processes. Later the nerve-muscle contacts became close and uninterrupted. There were no subneural folds of the sarcolemmal membrane at the new nerve-muscle junctions for the first few weeks after their formation but with longer survival subneural folds were formed. Degenerative changes occurred in some sole-plate nuclei. In the animals surviving 4 months or longer the end-plates of soleus fibres were similar to the normal for that muscle though nerve terminals were scattered along muscle fibres and many had no sole-plate nuclei near them. In gastrocnemius some end-plates were normal in appearance but others had unusually few and shallow subneural folds.
Publication Year: 1971
Publication Date: 1971-09-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 224
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