Synaptic Influences on Motoneurones of the Spinal Cord in Vertebrates

  • A. I. Shapovalov
  • N. P. Vesselkin


The mode of synaptic transmission between coupled spinal motoneurones and between primary somatic afferent fibres and motoneurones was studied in various vertebrate species. In frogs and carp the majority of interacting motoneurones were found to be coupled electrically. In lampreys, only electrotonic motoneuronal interactions were observed. In rats the interactions between motoneurones were found to be mostly mixed electrical and chemical ones. Direct monosynaptic control of motoneurones by the somatic primary afferents has been shown to occur in two aquatic species (lamprey, carp). Consequently, their mechanism does not depend on the presence of muscle spindles, which are absent in both species.

In the lamprey, carp and frog the transmission in these synapses is a bimodal electrical and chemical one.

Comparison between transmission modes in homologous rows of synapses reveals an evolutionary trend towards a decrease in the number of synapses exhibiting the electric mode of transmission.


Spinal Cord Ringer Solution Primary Afferents Synaptic Interaction Rana Ridibunda 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Arasaki, K., Kudo, M., and Nakanischi, T., 1984, Firing of spinal motoneurones due to electrical interaction in the rat: an in vitro study, Exp. Brain Res., 54: 437–445.PubMedCrossRefGoogle Scholar
  2. Auerbach, A.A., and Bennett, M.V.L., 1969, A rectifying electrotonic synapse in the central nervous system of a vertebrate, J. gen. Physiol., 53, 211–237.PubMedCrossRefGoogle Scholar
  3. Bando, T., 1975, Synaptic organization in teleost spinal motoneurons, Jap. J. Physiol., 25: 317–331.CrossRefGoogle Scholar
  4. Batueva, I. V., 1983, Properties of excitatory postsynaptic potentials elicited by stimulation of single segmental afferents in spinal motoneurones of the lamprey Lampetra fluviatilis, Zh. Evol. Biokhim. Fiziol., 19: 54–61.Google Scholar
  5. Batueva, I.V., Shapovalov, A.I. and Shiriaev, B.I., 1985, Combined morphological and electrophysiological description of connections between single primary afferent fibres and individual motoneurons in the frog and fish spinal cord, 5th International Symposium “Motor Control 85”. Abstracts, Warna, p. 15.Google Scholar
  6. Bennett, M.V.L., Sandri, C., Akert, K., 1978, Neuronal gap junctions and morphologically mixed synapses of the spinal cord of a teleost, Sternarchus albifrons (Gymnotoidei), Brain Res., 143: 43–60.PubMedCrossRefGoogle Scholar
  7. Brock, L.G., Coombs, J.C., and Eccles, J.C., 1952, The recording of potentials from motoneurones with an intracellular electrode, J. Physiology. 117: 431–460.Google Scholar
  8. Charlton, B.T., and Gray, E.G., 1966, Comparative electron microscopy of synapses in the vertebrate spinal cord. J. Cell Sci., 1: 67–80.PubMedGoogle Scholar
  9. Chung, J.M., Lee, K.H., Kin, J., and Coggeshall, R.E., 1985, Activation of dorsal horn cell by ventral root stimulation in the cat, J. NeuroPhysiol.,. 54: 261–272.PubMedGoogle Scholar
  10. Fulton, B.P., Miledi, R., and Takahashi, T., 1980, Electrical synapses between motoneurons in the spinal cord of the newborn rat, Proc. Roy. Soc. Lond., B208: 115–120.CrossRefGoogle Scholar
  11. Grinnell, A.D., 1966, A study of the interaction between motoneurones in the frog spinal cord, J. Physiol., 182: 612–648.PubMedGoogle Scholar
  12. Karamian, O.A., and Suderevskaya, E.L, 1986, Synaptic interactions between single spinal motoneurons, Neurophysiology (Neirofiziologiya), 18: 262–266.PubMedGoogle Scholar
  13. Magherini, P.C., Precht, W., Schwindt, P.C., 1976, Electrical properties of frog motoneurons in the in situ spinal cord. J. NeuroPhysiol., 39: 459–473.PubMedGoogle Scholar
  14. Motorina, M.V., 1978, Ultrastructure of synapses of gap junction type in the motor nuclei of the frog spinal cord, Arch. Anat., Histol & Embryol., 75: 27–34.Google Scholar
  15. Motorina, M.V., 1986, Electrotonic synapses in the spinal cord of mammalia, Arch. Anat., Histol. & Embryol., 91:13–20.Google Scholar
  16. Motorina, M.V., and Suderevskaya, E.L, 1983, Distribution of synaptic projections of the dorsal root in the spinal cord of the carp Cyprinus carpio, Zh Evol. Biokhim. Fiziol.. 19: 524–528.Google Scholar
  17. Schnitzlein, H.N., and Brown, H.K., 1975, Spinal motoneurons of the goldfish (Carassius auratus), Brain Behav., Evol., 12: 207–228.CrossRefGoogle Scholar
  18. Shapovalov, A.I., 1980, Interneuronal synapses with electrical, dual and chemical mode of transmission in vertebrates, Neuroscience, 5:1113–1124.PubMedCrossRefGoogle Scholar
  19. Shapovalov, A.I., 1983, Types of synaptic connections between nervous cells and their evolution, Zh. Evol. Biokhim. Fiziol., 19: 341–349.PubMedGoogle Scholar
  20. Shapovalov, A.I., and Batueva, I.V., 1984, Interactions between primary afferent fibres and motoneurones in the spinal cord of the river lamprey, Fiziol. Zh. SSSR. 70: 1178–1188.PubMedGoogle Scholar
  21. Shapovalov, A.I., and Shiriaev, B.I., 1978; Two types of electrotonic EPSP evoked in amphibian motoneurons by ventral root stimulation, Exp. Brain Res., 33: 313–323.PubMedGoogle Scholar
  22. Shapovalov, A.I., and Shiriaev, B.I., 1984, Synaptic interaction between single motoneurons in isolated spinal cord of frog, Neurophysiology (Neirofiziologiya), 16: 619–629.PubMedGoogle Scholar
  23. Shupljakov, O.V., 1986, Transmission in sensory-motor synapses in the lumbar spinal cord of the tadpoles Rana ridibunda, Zh. Evol. Biokhim. Fiziol., 22:174–180.Google Scholar
  24. Sotelo, C., and Taxi, J., 1970, Ultrastructural aspects of electrotonic junctions in the spinal cord of the frog, Brain Res., 17:137–141.PubMedCrossRefGoogle Scholar
  25. Sotelo, C., and Grofova, J., 1976, Ultrastructural features of neurons and synapses of the spinal cord, in: “Frog Neurobiology”, R. Llinas and W. Precht, eds, Springer, Berlin: pp. 707–727.CrossRefGoogle Scholar
  26. Suderevskaya, E.I., 1983, The study of motoneurons synaptic inputs in the isolated spinal cord of fish, in: “Neuron and interneuronal integration”, Nauka, Leningrad: pp. 54–55.Google Scholar
  27. Tamarova, Z.A., Shapovalov, A.L, and Shiriaev, B.I., 1978, Action of magnesium and manganese ions and calcium deficiency on the synaptic transmission in the isolated perfused rat spinal cord, Neurophysiology (Neirofiziologiya), 10: 530–533.PubMedGoogle Scholar
  28. Whiting, H.P., 1948, Nervous structure of the spinal cord of the young larval brook-lamprey, Quart. J. Micr. Sci. 89: 359–383.Google Scholar

Copyright information

© Springer Science+Business Media New York 1988

Authors and Affiliations

  • A. I. Shapovalov
    • 1
  • N. P. Vesselkin
    • 1
  1. 1.I.M. Sechenov Institute of Evolutionary Physiology and BiochemistryU.S.S.R. Academy of SciencesLeningradU.S.S.R.

Personalised recommendations