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  • 1
    Electronic Resource
    Electronic Resource
    Photoreceptors of a cyprinid fish, the roach: morphological and spectral characteristics (1986)
    Springer
    Journal of comparative physiology 159 (1986), S. 859-868 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Structure-function studies were undertaken on cones in the retina of the cyprinid fish, the roach,Rutilus rutilus, in order to provide a basis for analysis of colour information by post-receptoral neurones. Measurements were made with two main aims: (i) To determine by microspectrophotometry the absorbance spectra of the photopigments present within the retina, and correlate these with the morphological types of photoreceptor; (ii) To characterize the morphologies of the photoreceptors at both light and electron microscopical levels and determine their relative abundance in the retina. In addition to red-, green-, and blue-sensitive cones, an ultra-violet-sensitive photoreceptor has been found in a sub-population of miniature short single cones. Possible relevance of this finding to vertebrate vision is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00603739
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Plasticity of cone horizontal cell functioning in cyprinid fish retina: effects of background illumination of moderate intensity (1988)
    Springer
    Journal of neurocytology 17 (1988), S. 701-710 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In electrophysiological experiments involving intracellular recording from horizontal cells in the isolated retina of the roach, light adaptation of the retina has been shown to result in potentiation both of (1) the depolarizing component of biphasic chromaticity type S-potentials, and (2) the temporal frequency transfer functions of photopic luminosity type horizontal cells. Under identical light adaptation conditions, the number of spinules on horizontal cell dendrites positioned laterally at cone pedicle ribbon synapses, increase by some threefold. The latter effect occurs equally in pedicles of red- and green-sensitive cones. Thus, horizontal cells are ‘plastic’ in both structural and electrophysiological respects. Furthermore, since the two electrophysiological parameters studied depend on negative feedback from horizontal cells onto cones, the results suggest that it is the inhibitory synapses that are plastic and that spinules may be sites of the negative feedback interaction. Physiological and behavioural aspects of light-dependent horizontal cell plasticity are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01260997
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The cellular origin of an unusual type of S-potential: an intracellular horseradish peroxidase study in a cyprinid fish retina (1985)
    Springer
    Journal of neurocytology 14 (1985), S. 469-486 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary L2-type S-potentials are mainly blue/green-sensitive hyperpolarizing responses with a red-sensitive depolarizing component which is either weak or absent. They were first described in the retina of the roach, a cyprinid fish, by Djamgoz (1978, 1984) and Djamgoz & Ruddock (1978, 1979a). The cellular origin of these responses has been determined and characterized by intracellular recording, horseradish peroxidase staining, and light and electron microscopy. They were found to arise in horizontal cells with H2-like morphologies on average (Stell & Lightfoot, 1975). The dendrites of thesg cells contacted green- and blue-sensitive cone pedicles within which both lateral and central contacts were made at ribbon synapses. The laterally-positioned dendrites had incompletely formed spinules associated with them. A number of similarities between these units and the biphasic, chromaticity (Cb)-type S-potentials have been outlined and it is suggested that L2 units are essentially Cb-units with a weak depolarizing component. In turn, it is suggested that the depolarizing component is reduced as a consequence of the relatively dark-adapted states of the retinae. It is concluded that the negative feed-back pathway that subserves the generation of depolarizing (Cb-type) S-potentials is weak or absent in dark-adapted retinae and that spinules may be the site of this feed-back interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01217756
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Amacrine cells in the retina of a cyprinid fish: functional characterization and intracellular labelling with horseradish peroxidase (1989)
    Springer
    Cell & tissue research 256 (1989), S. 607-622 
    Details
    ISSN: 1432-0878
    Keywords: Retina ; Amacrine cells, sustained, transient ; Horseradish peroxidase ; Inner plexiform layer ; Rutilus rutilus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Forty amacrine cells in retinae of a cyprinid fish, the roach, were intracellularly labelled with horseradish peroxidase following electrophysiological identification as sustained depolarizing, sustained hyperpolarizing or transient units. Labelled cells were analysed by light microscopy and compared with a catalogue of amacrine cells established in a previous Golgi study on the same species. About 30% of the cell types characterized by the Golgi method were encountered in the present study. When intracellularly labelled cells were differentiated on the basis of their dendritic organization in the plane of the retina, a given electrophysiological response pattern was found to be generated by different morphological types, and vice versa. However, examination of the ramification patterns of the dendrites within the inner plexiform layer (i.e. in the radial dimension of the retina), showed that this morphological parameter of a given amacrine cell could be correlated with its light-evoked response. Several amacrine cell types were found to possess special distal dendrites which arose from the main dendritic branches and extended well over a mm in the retina. Distal dendrites were oriented tangentially with respect to the optic nerve papilla, but did not appear to be involved in any synaptic connectivity. It is concluded that the Golgi-based classification is a valuable tool for identifying intracellularly labelled amacrine cells. However, although the correlation between layering of dendrites in the inner plexiform layer and electrophysiology was generally good, additional physiological parameters would be required to determine whether more extensive parallels exist between structural and functional characteristics of amacrine cells. Alternatively, the considerable morphological diversity of amacrine cells may be of limited physiological significance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225611
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    Paper (German National Licenses)
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