Structures deprived of their innervation become supersensitive to their
normal chemical transmitter as well as to other substances (see Cannon &
Rosenblueth, 1949).
Nerve cells usually have a great number of fibres converging upon them
and are 'innervated' at numerous points of their surface (Wyckoff & Young
1956). Skeletal muscle fibres may also be innervated at more than one
point (Katz & Kuffler, 1941; Hunt & Kuffler, 1954), and slow muscle
fibres may have many synapses distributed along their length (Couteaux,
1955). This morphological feature immediately prompts the question as
to the effects of partial denervation of these tissues and how they compare
with those which follow complete denervation.