Abstract
A sublethal dose of tetanus toxin was injected into the leg muscles of the mouse and the motor end-plates were studied by electron microscopy. Slow muscle fibres are paralysed for several weeks because of the peripheral action of the toxin but fast muscles develop intense spasm because of its central action. Axonal sprouting from motor nerve terminals was found in slow (soleus) fibres but not in fast (superficial gastrocnemius) muscle. The axonal sprouts were enclosed in processes of Schwann cell cytoplasm and new end-plates were formed which were at first lacking in subneural folds. Dense granules accumulated between nerve and muscle in synaptic clefts at original as well as at newly formed end-plates. The origin and nature of these granules is uncertain at present. Degenerative changes in sole-plate nuclei, similar to those found after botulinum toxin, were observed. Motor end-plates in fast muscle fibres were normal.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
