Summary
During light-adaption dendrites of teleost horizontal cells form finger-like processes, called ‘spinules’, which are characterized by synaptic membrane densities. To investigate the involvement of cytoskeletal elements in the formation and retraction of spinules, effects of the microtubule and actin inhibitors colchicine and cytochalasin D were examined by injection into the vitreous. Both substances inhibited the light-induced spinule formation. The ultrastructural immunolocalization of tubulin revealed labelling of dendrites only in their proximal parts. The distal parts of dendrites which invaginate into cone pedicles were free of label. Treatment with anti-actin revealed immunoreactivity along the entire length of dendrites up to the dendritic terminals. The spinules, however, showed no labelling. This finding does not support the hypothesis that spinules are protruded by actin polymerization. After cytochalasin D treatment the density of label in the dendritic terminals was enhanced by a factor of three, which suggests an accumulation of actin. Thus, spinule inhibition by cytochalasin D is probably caused by distortion of a functional actin network in the dendritic terminals.
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Caceres, A., Binder, L. I., Payne, M. R., Bender, P., Rebhun, L. &Steward, O. (1984) Differential subcellular localization of tubulin and the microtubule-associated protein MAP2 in brain tissue as revealed by immunocytochemistry with monoclonal hybridoma antibodies.Journal of Neuroscience 4, 394–410.
Calverley, R. K. S. &Jones, D. G. (1990) Contributions of dendritic spines and perforated synapses to synaptic plasticity.Brain Research Reviews 15, 215–49.
Chang, F. -L. F. &Greenough, W. T. (1984) Transient and enduring morphological correlates of synaptic activity and efficacy change in the rat hippocampal slice.Brain Research 309, 35–46.
Cooper, J. A. (1987) Effects on cytochalasin and phalloidin on actin.Journal of Cell Biology 105, 1473–8.
Crick, F. (1982) Do dendritic spines twitch?Trends in Neurosciences 5, 44–6.
Djamgoz, M. B. A., Downing, J. E. G. &Wagner, H. -J. (1985) The cellular origin of an unusual type of S-potential: an intracellular horseradish study in a cyprinid fish.Journal of Neurocytology 14, 469–86.
Djamgoz, M. B. A., Kirsch, M. &Wagner, H. -J. (1989) Haloperidol suppresses light-induced spinule formation and biphasic responses of horizontal cells in fish (roach) retina.Neuroscience Letters 107, 200–4.
Fifkova, E. &Van Harrefeld, A. (1977) Long-lasting morphological changes in dendritic spines of dentate granular cells following stimulation of the entorhinal area.Journal of Neurocytology 6, 211–30.
Kirsch, M., Djamgoz, M. B. A. &Wagner, H. -J. (1990) Correlation of spinule dynamics and plasticity of the horizontal cell spectral response in cyprinid fish retina: quantitative analysis.Cell and Tissue Research 260, 123–30.
Kuznetsov, S. A., Langford, G. M. &Weiss, D. G. (1992) Actin-dependent organelle movement in squid axoplasm.Nature 356, 722–5.
Lynch, G. &Baudry, M. (1984) The biochemistry of memory: a new and specific hypothesis.Science 224, 1057–63.
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.
Morales, M. &Fifkova, E. (1989a)In situ localization of myosin and actin in dendritic spines with the immuno-gold technique.Journal of Comparative Neurology 279, 666–74.
Morales, M. &Fifkova, E. (1989b) Distribution of MAP2 in dendritic spines and its colocalization with actin.Cell and Tissue Research 256, 447–56.
Raynauld, J. P., Laviolette, J. R. &Wagner, H. -J. (1979) Goldfish retina: a correlate between cone activity and morphology of the horizontal cell in cone pedicles.Science 204, 1436–8.
Schliwa, M. (1982) Action of cytochalasin D on cytoskeletal networks.Journal of Cell Biology 92, 79–91.
Siman, R., Baudry, M. &Lynch, G. S. (1986) Calcium-activated proteases as possible mediators of synaptic plasticity. InSynaptic function (edited byEdelman, G. M., Gall, W. E. &Cowan, W. M.) pp. 519–48. New York: John Wiley and Sons.
Stell, W. K., Lightfoot, D. O., Wheeler, T. G. &Leeper, H. F. (1975) Goldfish retina: functional polarization of cone horizontal cell dendrites and synapses.Science 190, 989–90.
Stossel, T. P. (1989) From signal to pseudopod.Journal of Biological Chemistry 264, 18261–4.
Wagner, H. -J. (1980) Light-dependent plasticity of the morphology of horizontal cell terminals in cone pedicles of fish retinas.Journal of Neurocytology 9, 573–90.
Weeds, A. (1982) Actin-binding proteins — regulators of cell architecture and motility.Nature 296, 811–16.
Weiler, R. &Janssen, U. (1991) Synaptic spinule formation during light-adaptation is an actin-dependent process.Investigative Ophthalmology and Visual Science, Supplement 32, 2265.
Weiler, R. &Wagner, H. -J. (1984) Light-dependent change of cone-horizontal cell interactions in carp retina.Brain Research 298, 1–9.
Weiler, R., Kohler, K., Kirsch, M. &Wagner, H. -J. (1988) Glutamate and dopamine modulate synaptic plasticity in horizontal cell dendrites of fish retina.Neuroscience Letters 87, 205–9.
Woodford, B. J. &Blanks, J. C. (1989) Localization of actin and tubulin in developing and adult mammalian photo-receptors.Cell and Tissue Research 256, 495–505.
Wooley, C. S., Gould, E., Frankfurt, M. &McEwen, B. S. (1990) Naturally occuring fluctuation in dendritic spine density on adult hippocampal pyradmidal neurons.Journal of Neuroscience 10, 4035–9.
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Schmitz, Y., Kohler, K. Spinule formulation in the fish retina: is there an involvement of actin and tubulin? An electronmicroscopic immunogold study. J Neurocytol 22, 205–214 (1993). https://doi.org/10.1007/BF01246359
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DOI: https://doi.org/10.1007/BF01246359