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Studies on the site of termination of static and dynamic fusimotor fibres within muscle spindles of the tenuissimus muscle of the cat
Author(s) -
Brown M. C.,
Butler R. G.
Publication year - 1973
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1973.sp010323
Subject(s) - glycogen , stimulation , anatomy , chemistry , muscle spindle , mechanism (biology) , tetanic stimulation , biophysics , neuroscience , biology , biochemistry , physics , excitatory postsynaptic potential , receptor , quantum mechanics , afferent
1. The site of termination of static and dynamic fusimotor fibres has been mapped by finding which intrafusal muscle fibres have been depleted of glycogen as a result of tetanic stimulation of single γ fibres. Long periods of stimulation coupled with occlusion of the blood supply were necessary to cause glycogen depletion. 2. In cat tenuissimus muscle, dynamic γ motor fibres always activated bag intrafusal muscle fibres, and occasionally chain fibres. Static γ fibres always activated chain fibres and frequently activated bag fibres as well. 3. It is argued that these results can be fitted into the hypothesis of the mechanism of internal functioning of the spindle originally proposed by Jansen & Matthews (1962). It is also pointed out that the results raise problems concerning the mechanism of development of the spindle motor innervation.