Summary
To study the regenerative capacity of the spinal cord in adult rat, presynaptic boutons were classified as S (spherical vesicles), F (flattened vesicles) and C complexes, and analysed statistically on α-motoneuron somata and lamina VII interneurons on the operated side in the first segment rostral to a spinal cord hemisection. Following chloral hydrate anaesthesia left spinal cord hemisections were made on twenty adult rats (225 gms) at vertebral level T-2. Animals were prepared for electron microscopy at 7, 14, 30, 45, 60 and 90 DPO and compared with normals. All counts were made on coded material and subjected to statistical analysis. The normal frequency of presynaptic bouton types on α-motoneuron somata and primary dendrites was altered over the entire postoperative period. S presynaptic boutons were increased on α-motoneuron somata at 30 DPO. At 45 DPO, massive degeneration with concomitant synaptic remodeling resulted in a return to near normal frequencies of S and F presynaptic boutons. At 60 and 90 DPO a gain in S presynaptic boutons and a concomitant loss in F presynaptic boutons resulted in frequencies different from normal and decreased absolute numbers of presynaptic boutons. The interneuron somata also exhibited alterations over the postoperative period. There was a reversal of frequency of presynaptic boutons at 45 DPO. However unlike on α-motoneuron somata the frequency of S and F presynaptic boutons returned to normal at 60 and 90 DPO. The α-motoneuron somata appeared to be cyclically and nonselectively reinnervated by ventral horn interneurons over 90 DPO.
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References
Bernstein, J. J., andBernstein, M. E. (1971) Axonal regeneration and formation of synapses proximal to the site of lesion following hemisection of the rat spinal cord.Experimental Neurology 30, 336–51.
Bernstein, J. J., andBernstein, M. E. (1973a) Neuronal alteration and reinnervation following axonal regeneration and sprouting in mammalian spinal cord.Brain Behaviour and Evolution 8, 135–61.
Bernstein, J. J., andBernstein, M. E. (1976) Ventral horn synaptology in the rat.Journal of Neurocytology 5, 109–23.
Bernstein, J. J., Gelderd, J. B., andBernstein, M. E. (1974) Alteration of neuronal synaptic complement during regeneration and axonal sprouting of rat spinal cord.Experimental Neurology 44, 470–82.
Bernstein, M. E., andBernstein, J. J. (1973b) Regeneration of axons and synaptic complex formation rostral to the site of hemisection in the spinal cord of the monkey.International Journal of Neuroscience 5, 15–26.
Blinzinger, K., andKreutzberg, G. (1968) Displacement of synaptic terminals from regenerating motoneurons by microglial cells.Zeitschrift für Zellforschung und mikroskopische Anatomie 85, 145–57
Bodian, D. (1964) An electron-microscopic study of the monkey spinal cord. I Fine structure of normal motor column.Bulletin of the Johns Hopkins Hospital 114, 13–19.
Bodian, D. (1966a) Electron microscopy: Two major synaptic types on spinal motoneurons.Science 151, 1093–4.
Bodian, D. (1966b) Synaptic types on spinal motoneurons. An electron microscopic study.Bulletin of the Johns Hopkins Hospital 119, 16–45.
Bodian, D. (1972) Synaptic diversity and characterization by electron microscopy. InStructure and Function of Synapses. (Edited byPappas, G. D. andPurpura, D. P.) pp. 45–65. New York: Raven Press.
Bodian, D. (1975) Origin of specific synaptic types in the motoneuron neuropil of the monkey.Journal of Comparative Neurology 159, 225–43.
Brown, L. T., Jr. (1971) Projections and termination of the corticospinal tract in rodents.Experimental Brain Research 13, 432–50.
Chan-Palay, V. (1973) Neuronal plasticity in the cerebellar cortex and lateral nucleus.Zeitschrift für Anatomie und Entwicklungsgeschichte 142, 23–35.
Conradi, S. (1969a) Ultrastracture and distribution of neuronal and glial elements on the motoneuron surface in the lumbosacral spinal cord of the adult cat.Acta Physiologica Scandinavica Supplement332, 5–48.
Conradi, S. (1969b) Ultrastructure and distribution of neuronal and glial elements on the surface of the proximal part of a motoneuron dendrite, as analyzed by serial sections.Acta Physiologica Scandinavica Supplement332, 49–64.
Conradi, S. (1969c) Ultrastracture of dorsal root boutons on lumbosacral motoneurons of the adult cat, as revealed by dorsal root section.Acta Physiologica Scandinavica Supplement332, 85–115.
Goldberger, M. E. andMurray, M. (1974) Restitution of function and collateral sprouting in the cat spinal cord: The deafferented animal.Journal of Comparative Neurology 158, 37–54.
Goodman, D. C. andHorel, J. A. (1966) Sprouting of optic tract projections in the brain stem of the rat.Journal of Comparative Neurology 127, 71–88.
Kerns, J. M. andPeters, A. (1974) Ultrastructure of a large ventro-lateral dendritic bundle in the rat ventral horn.Journal of Neurocytology 3, 533–55.
Kerr, F. W. L. (1975) Neuroplasticity of primary afferents in the neonatal cat and some results of early deafferentation of the trigeminal spinal nucleus.Journal of Comparative Neurology 163, 305–27.
Liu, C. N. andChambers, W. W. (1958) Intraspinal sprouting of dorsal root axons.Archives of Neurology and Psychiatry 79, 46–61.
Lynch, G. andCotman, C. W. (1975) The hippocampus as a model for studying anatomical plasticity in the adult brain. InThe Hippocampus: Volume I: Structure and Development. (edited byIsaacson R. L. andPribram, K. H.) pp. 123–154. New York: Plenum.
Lynch, G., Stanfield, B. andCotman, C. (1973) Developmental differences in post-lesion axonal growth in the hippocampus.Brain Research 59, 155–68.
McLaughlin, B. (1972a) The fine structure of neurons and synapses in the motor nuclei of the cat spinal cord.Journal of Comparative Neurology 144, 429–60.
McLaughlin, B. (1972b) Dorsal root projections to the motor nuclei in the cat spinal cord.Journal of Comparative Neurology 144, 461–74.
McLaughlin, B. (1972c) Propriospinal and supraspinal projections to the motor nuclei of the cat spinal cord.Journal of Comparative Neurology 144, 475–500.
McLaughlin, B. J., Barber, R., Saito, K., Roberts, E., andWu, J. Y. (1975) Immunocytochemical localization of glutamate deearboxylase in rat spinal cord.Journal of Comparative Neurology 164, 305–21.
Mendell, L. M. andHenneman, E. (1971) Terminals of Single la fibers: location, density, and distribution within a pool of 300 homonymous motoneurons.Journal of Neurophysiology 34, 171–87.
Mendell, L. M., Munson, J. B. andScott, J. G. (1976) Alterations of synapses on axotomized motoneurons.Journal of Physiology 255, 67–79.
Murray, M. andGoldberger, M. E. (1974) Restitution of function and collateral sprouting in the cat spinal cord: The partially hemisected animal.Journal of Comparative Neurology 158, 19–36.
Raisman, G. (1969) Neuronal plasticity in the septal nuclei of the adult rat.Brain Research 14, 25–48.
Raisman, G., andField, P. (1973) A quantitative investigation of the development of collateral reinnervation after partial deafferentation of the septal nuclei.Brain Research 50, 241–64.
Raisman, G., andMatthews, M. R. (1972) Degeneration and regeneration of synapses. InThe Structure and Function of the Nervous System (edited byBourne, G.) pp. 61–104. New York: Academic Press.
Rustioni, A. andSotelo, C. (1974) Some effects of chronic deafferentation on the ultrastructure of the nucleus gracilis of the cat.Brain Research 73, 527–33.
Scheibel, M. E. andScheibel, A. B. (1970) Organization of spinal motoneuron dendrites and bundles.Experimental Neurology 28, 106–12.
Sotelo, C., andPalay, S. (1971) Altered axons and axon terminals in the lateral vestibular nucleus of the rat: possible example of axonal remodeling.Laboratory Investigation 25, 653–71.
Stewart, O., Cotman, C. andLynch, G. (1973) Re-establishment of electrophysiologically functional entorhinal cortical input to the dentate gyrus deafferented by ipsilateral entorhinal lesions: innervation by the contralateral entorhinal cortex.Experimental Brain Research 18, 396–414.
Sumner, B. E. H. (1975) A quantitative analysis of the response of presynaptic boutons to postsynaptic motor neuron axotomy.Experimental Neurology 46, 605–15.
Sumner, B. E. H. andSutherland, F. I. (1973) Quantitative electron microscopy on the injuréd hypoglossal nucleus in the rat.Journal of Neurocytology 2, 315–28.
Winer, B. J. (1971) InStatistical Principles in Experimental Design, pp. 191–5. New York: McGraw-Hill.
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Bernstein, M.E., Bernstein, J.J. Synaptic frequency alteration on rat ventral horn neurons in the first segment proximal to spinal cord hemisection: an ultrastructural statistical study of regenerative capacity. J Neurocytol 6, 85–102 (1977). https://doi.org/10.1007/BF01175416
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DOI: https://doi.org/10.1007/BF01175416