Rapid Neuronal and Glial Changes in the Phrenic Nucleus Following Spinal Cord Injury: A Possible Morphological Basis for the Unmasking of Functionally Ineffective Synapses

  • Harry G. Goshgarian
  • Jose A. Rafols
Part of the NATO ASI Series book series (NSSA, volume 172)


The present study describes specific morphological alterations of the normal ultrastructure of the rat phrenic nucleus which occur within four hours after an ipsilateral spinal cord hemisection. Qualitative and quantitative morphometric analyses demonstrated a rearrangement of the glial compartment and synaptic architecture in the phrenic neuropil. It is possible that the injury-induced neuronal and glial changes may be related to the unmasking of a latent motor pathway which restores function to muscle paralyzed by spinal cord injury.


Spinal Cord Spinal Cord Injury Injured Spinal Cord Glial Process Spinal Cord Injury Model 
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. Aserinsky, E., 1961, Effects of usage of a dormant respiratory, Exp.Neurol., 3:467–475.PubMedCrossRefGoogle Scholar
  2. Basbaum, A.I., and Wall, P.D., 1976, Chronic changes in the response of cells in adult cat dorsal horn following partial deafferentation. The appearance of responding cells in a previously non-responsive region, Brain Res., 116:181–204.PubMedCrossRefGoogle Scholar
  3. Berman, N., and Sterling, P., 1976, Cortical suppression of retinocollicular pathway in the monocularly deprived cat, J. Physiol. (Lond.), 225:263–274.Google Scholar
  4. Chatfield, P.O., and Mead, S., 1948, Role of the vagi in the crossed phrenic phenomenon, Am. J. Physiol., 54:417–422.Google Scholar
  5. Cotman, C.S., and Nieto-Sampedro, M., 1984, Cell biology of synaptic plasticity, Science, 225:1287–1294.PubMedCrossRefGoogle Scholar
  6. Cragg, B., and McLachlan, E., 1978, A mechanism for the observed recovery from ineffectiveness of synapses in the central nervous system, J. Theor. Biol., 71:433–440.PubMedCrossRefGoogle Scholar
  7. DeOlmos, J.S. and Heimer, L., 1977, Mapping of collateral projections with the HRP-method, Neurosci. Lett., 6:107–114.CrossRefGoogle Scholar
  8. Devor, M., 1983, Plasticity of spinal cord somatotopy in adult mammals: Involvement of relatively ineffective synapses. Birth Defects: Original Article series, 19:287–314.Google Scholar
  9. Devor, M., Basbaum, A.I., and Seltzer, Z., 1986, Spinal soma-totopic plasticity: Possible anatomical basis for somatotopically inappropriate connections. in: “Development and Plasticity of the Mammalian Spinal Cord”, M.E. Goldberger, A. Gorio and M. Murray, eds., Liviana, Padova, Italy.Google Scholar
  10. Devor, M., Merrill, E.G. and Wall, P.D., 1977, Dorsal horn cells that respond to stimulation of distant dorsal roots, J. Physiol. (Lond.), 270:519–531.Google Scholar
  11. Devor, M. and Wall, P.D., 1978, Reorganization of spinal cord sensory map after peripheral nerve injury, Nature, 275:75–76.CrossRefGoogle Scholar
  12. Devor, M. and Wall, P.D., 1981a, Effect of peripheral nerve injury on receptive fields of cells in the cat spinal cord, J. Comp. Neurol., 199(2): 277–291.PubMedCrossRefGoogle Scholar
  13. Devor, M. and Wall, P.D., 1981b, Plasticity in the spinal cord sensory map following peripheral nerve injury in rats, J. Neurosci., 1:679–684.PubMedGoogle Scholar
  14. Dostrovsky, J.O., Ball, G.J., Hu, J.N. and Sessle, B.J., 1982, Functional changes associated with partial tooth pulp removal in neurons of the trigeminal spinal tract nucleus, and their clinical implications. in: “Anatomical, Physiological and Pharmacological Aspects of Trigeminal Pain”, R.G. Hill and B. Matthews, eds., Excerpta Medica, Amsterdam.Google Scholar
  15. Dostrovsky, J.L., Millar, J., and Wall, P.D., 1976, The immediate shift of afferent drive of dorsal column nucleus cells following deafferentation in gracile nucleus and spinal cord, Exp. Neurol., 52:480–495.PubMedCrossRefGoogle Scholar
  16. Frank, J.I., 1980, Functional reorganization of cat somatic sensory-motor cortex (SMI) after selective dorsal root rhizotomies, Brain Res., 186:458–462.CrossRefGoogle Scholar
  17. Goshgarian, H.G., 1979, Development plasticity in the respiratory pathway of the adult rat, Exp. Neurol., 66:547–555.PubMedCrossRefGoogle Scholar
  18. Goshgarian, H.G., 1981, The role of cervical afferent nerve fiber inhibition of the crossed phrenic phenomenon, Exp. Neurol., 72:211–225.PubMedCrossRefGoogle Scholar
  19. Goshgarian, H.G., and Guth, L., 1977, Demonstration of functionally ineffective synapses in the guinea pig spinal cord, Exp. Neurol., 57:613–621.PubMedCrossRefGoogle Scholar
  20. Goshgarian, H.G., and Rafols, J.A., 1981, The phrenic nucleus of the albino rat: A correlative HRP and Golgi study, J. Comp. Neurol., 201:441–456.Google Scholar
  21. Goshgarian, H.G., and Rafols, J.A., 1984, The ultrastructure and synaptic architecture of phrenic motor neurons in the spinal cord of the adult rat, J. Neurocytol., 13:85–109.PubMedCrossRefGoogle Scholar
  22. Guth, L., 1976, Functional plasticity in the respiratory pathway of the mammalian spinal cord, Exp. Neurol., 51:414–420.PubMedCrossRefGoogle Scholar
  23. Hatton, G.I., 1985, Reversible synapse formation and modulation of cellular relationships in the adult hypothalamus under physiological conditions, in: “Synaptic Plasticity”, C.W. Cotman, ed., Guilford Press, New York.Google Scholar
  24. Hatton, G.I., 1986, Plasticity in the hypothalamic magnocellular neurosecretory system, Fed. Proc., 45:2328–2333.PubMedGoogle Scholar
  25. Hatton, G.I., Perlmutter, L.S., Salm, A.K., and Tweedle, CD., 1984, Dynamic neuronal-glial interactions in hypothalamus and pituitary: Implications for control of hormone synthesis and release, Peptides., 5 (suppl. 1): 121–138.PubMedCrossRefGoogle Scholar
  26. Merril, E.G., and Wall, P.D., 1972, Factors forming the edge of a receptive field. The presence of relatively ineffective afferents, J. Physiol. (Lond.), 226:825–846.Google Scholar
  27. Millar, J., Basbaum, A.I., and Wall, P.D., 1976, Restructing the somatotopic map and appearance of abnormal neuronal activity in the gracile nucleus after partial deaffer-entation, Exp. Neurol., 50:658–672.PubMedCrossRefGoogle Scholar
  28. Porter, W.T., 1895, The path of the respiratory impulse from the bulb to the phrenic nuclei, J. Physiol. (Lond.), 17:455–485.Google Scholar
  29. Rhoades, R.W., Belford, G.R., and Killackey, H.P., 1987, Receptive-field properties of rat ventral posterior medial neurons before and after selective kainic acid lesions of the trigeminal brain stem complex, J. Neurophysiol., 57:1557–1600.Google Scholar
  30. Seltzer, Z., and Devor, M., 1984, Effect of nerve section on the spinal distribution of neighboring nerves, Brain Res., 306:31–37.PubMedCrossRefGoogle Scholar
  31. Wall, P.D., 1977, The presence of ineffective synapses and the circumstances of neighboring nerves, Brain Res., 306:31–37.Google Scholar
  32. Wall, P.D., and Egger, M.D., 1971a, Formation of new connections in adult rat brains after partial deafferentation, Nature, 232:542–545.PubMedCrossRefGoogle Scholar
  33. Wall, P.D., and Egger, M.D., 1971b, The plantar cushion reflex circuit: An oligosynaptic reflex, J. Physiol. (Lond.), 216:483–501.Google Scholar

Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • Harry G. Goshgarian
    • 1
  • Jose A. Rafols
    • 1
  1. 1.Department of Anatomy and Cell BiologyWayne State University School of MedicineDetroitUSA

Personalised recommendations