Summary
Postsynaptic densities (PSDs) isolated from rat forebrain were examined in samples prepared for electron microscopy by negative staining. Two structurally distinct areas could be distinguished within each individual PSD, a peripheral zone composed of a planar array of spherical subunits with a mean diameter of 18 nm and one or more islands of fine granular material enclosed by the subunits. These enclosures correspond in distribution and size to ‘holes’ which are known to occur in PSDs in intact brain tissue. The spherical subunits can occur singly in the isolated PSD preparations showing that the structure of each individual subunit does not depend upon its interaction with others. These observations indicate that the PSD structure has both regular and differentiated features. These are considered in relation to the possible roles of the PSD in defining the postsynaptic locus and mediating the postsynaptic events of synaptic transmission.
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References
Blomberg, F., Cohen, R. S. &Siekevitz, P. (1977) The structure of postsynaptic densities isolated from dog cerebral cortex. II. Characterization and arrangement of some of the major proteins within the structure.Journal of Cell Biology 74, 204–25.
Bloom, F. E. &Aghajanian, G. K. (1966) Cytochemistry of synapses: A selective staining method for electron microscopy.Science 154, 1575–7.
Boublik, M., Hellmann, W. &Kleinschmidt, A. K. (1977) Size and structure of E.coli ribosomes by electron microscopy.European Journal of Cell Biology 14, 293–300.
Carlin, R. K., Grab, D. J., Cohen, R. S. &Siekevitz, P. (1980) Isolation and characterization of postsynaptic densities from various brain regions: Enrichment of different types of postsynaptic densities.Journal of Cell Biology 86, 831–43.
Cohen, R. S., Blomberg, P., Berzins, K. &Siekevitz, P. (1977) The Structure of postsynaptic densities isolated from dog cerebral cortex. I. Overall morphology and protein composition.Journal of Cell Biology 74, 181–203.
Cohen, R. S. &Siekevitz, P. (1978) The form of the postsynaptic density: A serial section study.Journal of Cell Biology 78, 36–46.
Cotman, C. W. &Taylor, D. (1974) Localization and characterization of Con A receptors in the synaptic cleft.Journal of Cell Biology 62, 236–42.
Cotman, C. W., Banker, G., Churchill, L. &Taylor, D. (1974) Isolation of postsynaptic densities from rat brain.Journal of Cell Biology 63, 441–55.
Grab, D. J., Berzins, K., Cohen, R. S. &Siekevitz, P. (1979) Presence of calmodulin in postsynaptic densities isolated from canine cerebral cortex.Journal of Biological Chemistry 254, 8690–6.
Gray, E. G. (1959) Axo-somatic and axo-dendritic synapses of cerebral cortex. An electron microscopic study.Journal of Anatomy 93, 420–33.
Jones, D. H. &Matus, A. I. (1974) Isolation of synaptic plasma membrane from brain by combined flotation-sedimentation density gradient centrifugation.Biochimica Biophysica Acta 356, 276–87.
Kelly, P. T. &Cotman, C. W. (1978) Synaptic proteins. Characterization of tubulin and actin and identification of a distinct postsynaptic density protein.Journal of Cell Biology 79, 173–83.
Kelly, P. T. &Cotman, C. W. (1979) Cyclic AMP-stimulated protein kinases at brain synaptic junctions.Journal of Biological Chemistry 254, 1564–75.
Matus, A., Pehling, G. &Wilkinson, D. (1981) γ-Aminobutyric acid receptors in brain postsynaptic densities.Journal of Neurobiologe 12, 67–73.
Matus, A. I. &Taff-Jones, D. H. (1978) Morphology and molecular composition of isolated post-synaptic junctional structure.Proceedings of the Royal Society of London, Series B 203, 135–51.
Matus, A., Pehling, G., Ackermann, M. &Maeder, J. (1980) Brain postsynaptic densities: Their relationship to glial and neuronal filaments.Journal of Cell Biology 87, 346–59.
Matus, A., De Petris, S. &Raff, M. C. (1973) Mobility of Con A receptors in myelin and synaptic membranes.Nature 244, 278–9.
Matus, A. I. &Walters, B. B. (1975) Ultrastructure of the synaptic junctional lattice isolated from mammalian brain.Journal of Neurocytology 4, 369–75.
Matus, A. I. &Walters, B. B. (1976) Type 1 and 2 synaptic junctions: Differences in distribution of concanavalin A binding sites and stability of the junctional adhesion.Brain Research 108, 249–56.
Matus, A. I., Walters, B. B. &Jones, D. H. (1975) Junctional ultrastructure in isolated synaptic membranes.Journal of Neurocytology 4, 357–67.
Ng, M. &Matus, A. (1979) Protein phosphorylation in isolated plasma membranes and postsynaptic junctional structures from brain synapses.Neuroscience 4, 169–80.
Palay, S. L. (1958) The morphology of synapses in the central nervous system.Experimental Cell Research 5, Suppl. 275–93.
Peters, A. &Kaiserman-Abramof, I. R. (1969) The small pyramidal neuron of the rat cerebral cortex.Zeitschrift für Zellforschung und mikroskopische Anatomie 100, 487–506.
Wuerker, R. B. (1970) Neurofilaments.Tissue and Cell 2, 1–9.
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Matus, A., Ackermann, M. & Pehling, G. Regularity and differentiation within the structure of brain postsynaptic densities. J Neurocytol 10, 889–896 (1981). https://doi.org/10.1007/BF01258520
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DOI: https://doi.org/10.1007/BF01258520