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. 1978 Aug;281:301–313. doi: 10.1113/jphysiol.1978.sp012423

A morphological study of the axons and recurrent axon collaterals of cat alpha-motoneurones supplying different functional types of muscle unit.

S Cullheim, J O Kellerth
PMCID: PMC1282698  PMID: 702385

Abstract

1. Cat alpha-motoneurones supplying muscle units of the soleus S type and gastrocnemius S, FR and FF types were injected intracellularly with horseradish peroxidase. 2. Ten alpha-motoneurones of each motor unit type were collected for morphological analysis of the intramedullary parts of their axonal systems including the recurrent axon collaterals. 3. The alpha-motor axon diameters in the spinal cord white matter were significantly smaller for the soleus motor units (mean = 5.2 micrometer) than for the gastrocnemius S units (mean = 6.4 micrometer), which in turn differed significantly from those of the gastrocnemius FR (mean 7.4 micrometer) and FF (mean = 7.3 micrometer types. 4. The number of axon collateral outbulgings, interpreted as synaptic terminals, which originated from the soleus motor axons (mean = 27.8) was significantly smaller, white that of the gastrocnemius FF motor axons (mean = 98.1) was significantly larger, than the number of outbulgings from the gastrocnemius S (mean = 44.4) and FR (mean = 53.8) motor axons. The latter two types were not significantly different. 5. In transverse sections the axon collateral outbulgings were found not only in the classical Renshaw cell area ventromedial to the main motor nuclei but also within the homonymous motor nucleus. However, only some of the neurones projected to the latter area. Rostrocaudally, the outbulgings were distributed within a distance of less than 1 mm around the position of the parent cell bodies. 6. Some physiological implications of the observed differences between axon collateral systems of various functional types of alpha-motoneurones were discussed in relation to the present knowledge of the effects of the recurrent axon collaterals during different types of involuntary and voluntary activation of the alpha-motoneurones.

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Selected References

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  1. Burke R. E. Firing patterns of gastrocnemius motor units in the decerebrate cat. J Physiol. 1968 Jun;196(3):631–654. doi: 10.1113/jphysiol.1968.sp008527. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Burke R. E., Levine D. N., Salcman M., Tsairis P. Motor units in cat soleus muscle: physiological, histochemical and morphological characteristics. J Physiol. 1974 May;238(3):503–514. doi: 10.1113/jphysiol.1974.sp010540. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Burke R. E., Levine D. N., Tsairis P., Zajac F. E., 3rd Physiological types and histochemical profiles in motor units of the cat gastrocnemius. J Physiol. 1973 Nov;234(3):723–748. doi: 10.1113/jphysiol.1973.sp010369. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Burke R. E., Levine D. N., Zajac F. E., 3rd Mammalian motor units: physiological-histochemical correlation in three types in cat gastrocnemius. Science. 1971 Nov 12;174(4010):709–712. doi: 10.1126/science.174.4010.709. [DOI] [PubMed] [Google Scholar]
  5. Burke R. E., Rymer W. Z. Relative strength of synaptic input from short-latency pathways to motor units of defined type in cat medial gastrocnemius. J Neurophysiol. 1976 May;39(3):447–458. doi: 10.1152/jn.1976.39.3.447. [DOI] [PubMed] [Google Scholar]
  6. Cullheim S., Kellerth J. O. A morphological study of the axons and recurrent axon collaterals of cat alpha-motoneurones supplying different hind-limb muscles. J Physiol. 1978 Aug;281:285–299. doi: 10.1113/jphysiol.1978.sp012422. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cullheim S., Kellerth J. O., Conradi S. Evidence for direct synaptic interconnections between cat spinal alpha-motoneurons via the recurrent axon collaterals: a morphological study using intracellular injection of horseradish peroxidase. Brain Res. 1977 Aug 19;132(1):1–10. doi: 10.1016/0006-8993(77)90702-8. [DOI] [PubMed] [Google Scholar]
  8. ECCLES J. C., ECCLES R. M., IGGO A., ITO M. Distribution of recurrent inhibition among motoneurones. J Physiol. 1961 Dec;159:479–499. doi: 10.1113/jphysiol.1961.sp006822. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. GRANIT R., HENATSCH H. D., STEG G. Tonic and phasic ventral horn cells differentiated by post-tetanic potentiation in cat extensors. Acta Physiol Scand. 1956 Sep 26;37(2-3):114–126. doi: 10.1111/j.1748-1716.1956.tb01347.x. [DOI] [PubMed] [Google Scholar]
  10. GRANIT R., PASCOE J. E., STEG G. The behaviour of tonic alpha and gamma motoneurones during stimulation of recurrent collaterals. J Physiol. 1957 Oct 30;138(3):381–400. doi: 10.1113/jphysiol.1957.sp005857. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hammarberg C., Kellerth J. O. Studies of some twitch and fatigue properties of different motor unit types in the ankle muscles of the adult cat. Acta Physiol Scand. 1975 Nov;95(3):231–242. doi: 10.1111/j.1748-1716.1975.tb10047.x. [DOI] [PubMed] [Google Scholar]
  12. Hellweg C., Meyer-Lohmann J., Benecke R., Windhorst U. Responses of Renshaw cells to muscle ramp stretch. Exp Brain Res. 1974;21(4):353–360. doi: 10.1007/BF00237898. [DOI] [PubMed] [Google Scholar]
  13. KUNO M. Excitability following antidromic activation in spinal motoneurones supplying red muscles. J Physiol. 1959 Dec;149:374–393. doi: 10.1113/jphysiol.1959.sp006345. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Pierrot-Deseilligny E., Morin C., Katz R., Bussel B. Influence of voluntary movement and posture on recurrent inhibition in human subjects. Brain Res. 1977 Apr 1;124(3):427–436. doi: 10.1016/0006-8993(77)90944-1. [DOI] [PubMed] [Google Scholar]
  15. Pompeiano O., Wand P., Sontag K. H. The sensitivity of Renshaw cells to velocity of sinusoidal stretches of the triceps surae muscle. Arch Ital Biol. 1975 Jul;113(3):280–294. [PubMed] [Google Scholar]
  16. ROMANES G. J. The motor cell columns of the lumbo-sacral spinal cord of the cat. J Comp Neurol. 1951 Apr;94(2):313–363. doi: 10.1002/cne.900940209. [DOI] [PubMed] [Google Scholar]
  17. Ryall R. W., Piercey M. F., Polosa C., Goldfarb J. Excitation of Renshaw cells in relation to orthodromic and antidromic excitation of motoneurons. J Neurophysiol. 1972 Jan;35(1):137–148. doi: 10.1152/jn.1972.35.1.137. [DOI] [PubMed] [Google Scholar]
  18. Severin F. V., Orlovskii G. N., Shik M. L. Vozvratnye vliianiia na rabotu odinochnykh motoneironov pri upravliaemoi lokomotsii. Biull Eksp Biol Med. 1968;66(7):5–9. [PubMed] [Google Scholar]
  19. Smith J. L., Edgerton V. R., Betts B., Collatos T. C. EMG of slow and fast ankle extensors of cat during posture, locomotion, and jumping. J Neurophysiol. 1977 May;40(3):503–513. doi: 10.1152/jn.1977.40.3.503. [DOI] [PubMed] [Google Scholar]

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