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Effects of impulse blockade on the contractile properties of rat skeletal muscle.
Author(s) -
Kowalchuk N,
McComas A
Publication year - 1987
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.1987.sp016366
Subject(s) - denervation , chemistry , soleus muscle , anatomy , plantaris muscle , contraction (grammar) , stimulation , atrophy , skeletal muscle , medicine , tetanic stimulation , endocrinology , excitatory postsynaptic potential , receptor , biochemistry
1. Pressure was used to produce a localized block of impulse conduction in motor nerve fibres supplying rat plantaris and soleus muscles. After 1 week of inactivity both muscles exhibited marked atrophy of type I and type II muscle fibres. 2. In treated plantaris and soleus muscles the specific tetanic tensions were reduced to approximately half those of untreated control muscles; the specific twitch tensions were unchanged. The fall in specific tetanic tension in the nerve‐blocked muscles was not associated with impaired excitation of muscle fibres during repetitive stimulation. 3. In nerve‐blocked plantaris muscles the contraction and half‐relaxation times became significantly prolonged whereas no change could be demonstrated in similarly treated soleus muscles. In both muscles the maximum rates of tetanic tension development increased following nerve block. 4. It is concluded that, in the rat, most of the changes in contractile properties and in muscle fibre size which follow denervation may be attributed to disuse rather than to interruption of axoplasmic transport.