Abstract
1. Isometric contractions of motor units have been studied in self-reinnervated soleus and flexor digitorum longus muscles, the motor nerves of which had been transected 6 months earlier.
2. The distributions of motor unit tetanic tensions in both muscles were skewed towards large values and showed greater variance than normal: there were motor units which produced more tension and others which developed less tension than in control muscles. Mean tensions of motor units are compared with those of the controls.
3. The variance of times to peak of motor units in both muscles was significantly smaller than normal.
4. Conduction velocities of axons were slower than normal above the point of nerve section. A number of axons did not functionally cross this point and those that did conducted slowly below the neuroma.
5. Many of the correlations seen in normal muscle between axon conduction velocity, motor unit tetanic tension, twitch time to peak and ratio of twitch to tetanic tension were demonstrated in reinnervated muscle.
6. We suggest that the pattern of motor unit organization in self-reinnervated muscle can in part be due to random regrowth of axons but is largely produced by specific processes related to axon size which are not identical in fast and slow muscle.
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Selected References
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- BESSOU P., EMONET-DENAND F., LAPORTE Y. [Relation between the conduction rate of motor nerve fibers and the contraction time of their motor units]. C R Hebd Seances Acad Sci. 1963 Jun 24;256:5625–5627. [PubMed] [Google Scholar]
- BULLER A. J., LEWIS D. M. FURTHER OBSERVATIONS ON MAMMALIAN CROSS-INNERVATED SKELETAL MUSCLE. J Physiol. 1965 May;178:343–358. doi: 10.1113/jphysiol.1965.sp007631. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BULLER A. J., LEWIS D. M. FURTHER OBSERVATIONS ON THE DIFFERENTIATION OF SKELETAL MUSCLES IN THE KITTEN HIND LIMB. J Physiol. 1965 Feb;176:355–370. doi: 10.1113/jphysiol.1965.sp007555. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bagust J., Knott S., Lewis D. M., Luck J. C., Westerman R. A. Isometric contractions of motor units in a fast twitch muscle of the cat. J Physiol. 1973 May;231(1):87–104. doi: 10.1113/jphysiol.1973.sp010221. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bagust J., Lewis D. M., Westerman R. A. The properties of motor units in a fast and a slow twitch muscle during post-natal development in the kitten. J Physiol. 1974 Feb;237(1):75–90. doi: 10.1113/jphysiol.1974.sp010470. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eccles J. C., Eccles R. M., Kozak W. Further investigations on the influence of motoneurones on the speed of muscle contraction. J Physiol. 1962 Sep;163(2):324–339. doi: 10.1113/jphysiol.1962.sp006978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gwyn D. G., Aitken J. T. The formation of new motor endplates in mammalian skeletal muscle. J Anat. 1966 Jan;100(Pt 1):111–126. [PMC free article] [PubMed] [Google Scholar]
- Kugelberg E., Edström L., Abbruzzese M. Mapping of motor units in experimentally reinnervated rat muscle. Interpretation of histochemical and atrophic fibre patterns in neurogenic lesions. J Neurol Neurosurg Psychiatry. 1970 Jun;33(3):319–329. doi: 10.1136/jnnp.33.3.319. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lewis D. M. The effect of denervation on the mechanical and electrical responses of fast and slow mammalian twitch muscle. J Physiol. 1972 Apr;222(1):51–75. doi: 10.1113/jphysiol.1972.sp009787. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weeds A. G., Pope B. Chemical studies on light chains from cardiac and skeletal muscle myosins. Nature. 1971 Nov 12;234(5324):85–88. doi: 10.1038/234085a0. [DOI] [PubMed] [Google Scholar]
- YAHR M. D., HERZ E., MOLDAVER J., GRUNDFEST H. Electromyographic patterns in reinnervated muscle. Arch Neurol Psychiatry. 1950 May;63(5):728–738. doi: 10.1001/archneurpsyc.1950.02310230050004. [DOI] [PubMed] [Google Scholar]