Skip to main content
Log in

Equidensitometric analytical techniques applied to the study of synaptic ultrastructure

  • Published:
Journal of Neurocytology

Summary

Equidensitometric analytical techniques have been utilized in the study of synaptic ultrastructure. Selection of micrographs was made using three criteria; namely difficulty of interpretation of the micrographs, the need for quantitative investigation of them and the possibility that a greater degree of information might be extracted from them. The majority of junctions investigated were of E-PTA material, although conventionally prepared material was also analysed. Equidensitometry usingAgfacontour Professional film permitted three approaches: screen equidensities (substituting characteristic symbols for densities), line equidensities (lines joining points of equal density) and families of equidensities (where a number of line equidensities are assembled and printed together). Screen and line equidensities proved of most value in the profiles examined, the former for providing information regarding the substructure of paramembranous components (dense projections, cleft densities and postsynaptic densities) and the latter for clearly delineating and separating these components.

While these techniques cannot increase the information content inherent in the original electron micrographs, they aid interpretation for two reasons: the elimination of background noise in the line equidensity and the quantification of micrographs by the substitution of symbols for areas of equal density in screen equidensities. This report demonstrates the potential of these analytical procedures for synaptic ultrastructural studies, while at the same time obviating the necessity of the purchase of elaborate equipment.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Adams, D. andWhittaker, D. K. (1972) Desmosome structure in human foetal epithelia.Micron 3, 186–95.

    Google Scholar 

  • Aghajanian, G. K. andBloom, F. E. (1967) The formation of synaptic junctions in developing rat brain: a quantitative electron microscopic study.Brain Research 6, 716–27.

    PubMed  Google Scholar 

  • Akert, K., Kawana, E. andSandri, C. (1971) ZIO-positive and ZIO-negative vesicles in nerve terminals.Progress in Brain Research 34, 305–17.

    Google Scholar 

  • Akert, K., Moor, H., Pfenninger, K. andSandri, C. (1969) Contribution of new impregnation methods and freeze-etching to the problems of synaptic fine structure.Progress in Brain Research 31, 223–40.

    PubMed  Google Scholar 

  • Akert, K. andPfenninger, K. (1969) Synaptic fine structure and neural dynamics. InCellular Dynamics of the Neuron, ISCB Symposium Paris, Vol. 8, (edited byBarondes, S. H.) pp. 245–60. New York: Academic Press.

    Google Scholar 

  • Akert, K., Pfenninger, K., Sandri, C. andMoor, H. (1972) Freeze etching and cytochemistry of vesicles and membrane complexes in synapses of the central nervous sytem. InStructure and Function of Synapses, (edited byPappas, G. D. andPurpura, D. P.) pp. 67–86. New York: Raven Press.

    Google Scholar 

  • Akert, K. andSandri, C. (1968) An electron microscopic study of zinc iodine—osmium impregnation of neurons. I. Staining of synaptic vesicles at cholinergic junctions.Brain Research 7, 286–95.

    PubMed  Google Scholar 

  • De Robertis, E. (1966) Synaptic complexes and synaptic vesicles as structural and biochemical units of the central nervous system. InNerve as a Tissue, (edited byRodahl, K. andIssekutz, B.) pp. 88–115. New York: Hoeber.

    Google Scholar 

  • Gray, E. G. (1966) Problems of interpreting the fine structure of vertebrate and invertebrate synapses.International Review of General and Experimental Zoology 2, 139–70.

    Google Scholar 

  • Gray, E. G. andGuillery, R. W. (1966) Synaptic morphology in the normal and degenerating nervous system.International Review of Cytology 19, 111–82.

    PubMed  Google Scholar 

  • Gray, E. G. andWillis, R. A. (1970) On synaptic vesicles, complex vesicles and dense projections.Brain Research 24, 147–68.

    Google Scholar 

  • Heidenreich, J., Bethge, H. andRuess, V. (1964) Zur objektiven Auswertung von Auflosungstest-Aufnahmen.Proceedings of the Third European Regional Conference of Electron Microscopy, Prague 1, 125.

    Google Scholar 

  • Holst, M. C. andWatson, C. R. R. (1973) Some ultrastructural features of the inferior olivary nucleus of the echidna.Journal of Anatomy (London) 114, 153.

    Google Scholar 

  • Jones, D. G. (1968) The fine structure of the synaptic membrane adhesions on octopus synaptosomes.Zeitschrift für Zellforschung und Mikroskopische Anatomie 88, 457–69.

    Google Scholar 

  • Jones, D. G. (1969) The morphology of the contact region of vertebrate synaptosomes.Zeitschrift für Zellforschung und Mikroskopische Anatomie 95, 263–79.

    Google Scholar 

  • Jones, D. G. (1970a) A further contribution to the study of the contact region ofOctopus synaptosomes.Zeitschrift für Zellforschung und Mikroskopische Anatomie 103, 48–60.

    Google Scholar 

  • Jones, D. G. (1970b) A study of the presynaptic network ofOctopus synaptosomes.Brain Research 20, 145–58.

    PubMed  Google Scholar 

  • Jones, D. G. (1973) Some factors affecting the PTA staining of synaptic junctions: a preliminary comparison of PTA stained junctions in various regions of the CNS.Zeitschrift für Zellforschung und Mikroskopische Anatomie 143, 301–12.

    Google Scholar 

  • Jones, D. G. andBradford, H. F. (1971) The relationship between complex vesicles, dense-cored vesicles and dense projections in cortical synaptosomes.Tissue and Cell 3, 177–90.

    Google Scholar 

  • Jones, D. G. andBrearley, R. F. (1972a) Further studies on synaptic junctions. I. Ultrastructural features in intact rat cerebral cortex.Zeitschrift für Zellforschung und Mikroskopische Anatomie 125, 415–31.

    Google Scholar 

  • Jones, D. G. andBrearley, R. F. (1972b) Further studies on synaptic junctions. II. A comparison of synaptic ultrastructure in fractionated and intact cerebral cortex.Zeitschrift für Zellforschung und Mikroskopische Anatomie 125, 432–47.

    Google Scholar 

  • Jones, D. G. andBrearley, R. F. (1973) An analysis of some aspects of synaptosomal ultrastructure by the use of serial sections.Zeitschrift für Zellforschung und Mikroskopische Anatomie 140, 481–96.

    Google Scholar 

  • Jones, D. G., Brearley, R. F. andDoran, G. A. (1972) The organization of dense projections in synapses of the brain of a marsupial,Setonix brachyurus.Anatomical Record 174, 39–46.

    PubMed  Google Scholar 

  • Kanaseki, T. andKadota, K. (1969) The ‘vesicle in a basket’. A morphological study of the coated vesicle isolated from the nerve endings of the guinea-pig brain, with special reference to the mechanism of membrane movements.Journal of Cell Biology 42, 202–20.

    PubMed  Google Scholar 

  • Krug, W. andSchusta, J. (1958) Elektronische Aquidensitenherstellung.Optik 15, 145–52.

    Google Scholar 

  • Lau, E. andHess, G. (1960) Photographische Grossflachenphotometric.Bild Und Ton 13, 71–3.

    Google Scholar 

  • Lau, E. andKrug, W. (1968)Equidensitometry, London: Focal Press.

    Google Scholar 

  • Martin, R., Barlow, J. andMiralto, A. (1969) Application of the zinc iodide—osmium tetroxide impregnation of synaptic vesicles in cephalopod nerves.Brain Research 15, 1–16.

    PubMed  Google Scholar 

  • Moor, H., Pfenninger, K. andAkert, K. (1969) Synaptic vesicles in electron micrographs of freeze-etched nerve terminals.Science 164, 1405–7.

    PubMed  Google Scholar 

  • Nolan, T. M. andJones, D. G. (1973) Morphometry of synaptic ultrastructure using equidensitometry.American Journal of Anatomy 138, 527–31.

    PubMed  Google Scholar 

  • Peters, A., Palay, S. L. andWebster, H. De F. (1970)The Fine Structure of the Nervous System — The Cells and their Processes. New York: Harper and Row.

    Google Scholar 

  • Pfenninger, K., Akert, K., Moor, H. andSandri, C. (1972) The fine structure of freeze-fractured presynaptic membranes.Journal of Neurocytology 1, 129–49.

    PubMed  Google Scholar 

  • Pfenninger, K., Sandri, C., Akert, K. andEugster, C. H. (1969) Contribution to the problem of structural organization of the presynaptic area.Brain Research 12, 10–18.

    PubMed  Google Scholar 

  • Robertson, J. D. (1963) The occurrence of a subunit pattern in the unit membranes of club endings in Mauthner cell synapses in goldfish brains.Journal of Cell Biology 19, 201–21.

    PubMed  Google Scholar 

  • Robertson, J. D. (1966) Current problems of unit membrane structure and contact relationships. InNerve as a Tissue, (edited byRodahl, K. andIssekutz, B.) pp. 11–48. New York: Hoeber.

    Google Scholar 

  • Van Der Loos, H. (1963) Fine structure of synapses in the cerebral cortex.Zeitschrift für Zellforschung und Mikroskopische Anatomie 60, 815–25.

    Google Scholar 

  • Weibel, E. R. (1969) Techniques for quantitative evaluation of structure. ‘Morphometry’.International Review of Cytology 26, 235–302.

    PubMed  Google Scholar 

  • Weibel, E. R. andElias, H. (1967)Quantitative Methods in Morphology. Berlin: Springer.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Nolan, T.M., Jones, D.G. Equidensitometric analytical techniques applied to the study of synaptic ultrastructure. J Neurocytol 3, 327–340 (1974). https://doi.org/10.1007/BF01097917

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01097917

Keywords

Navigation