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  • 1
    Electronic Resource
    Electronic Resource
    The effects of constant light and constant darkness on daily changes in the morphology of the pineal organ in the goldfish,Carassius auratus (1982)
    Springer
    Journal of neural transmission 53 (1982), S. 277-292 
    Details
    ISSN: 1435-1463
    Keywords: Pineal organ ; goldfish ; circadian rhythm ; constant light ; constant darkness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of photoreceptor cells in the pineal organ of the goldfish was found to vary quantitatively over a 24-hour period. Stereological analysis revealed significant daily changes in the volume of the cell and inner segment, nuclear volume and nucleolar diameter, volume of endo-plasmic reticulum and Golgi bodies, area of both rough and smooth endo-plasmic reticulum, and number of vesicles associated with each Golgi body. Peak values of these variables occurred either during the dark phase or latter part of the light phase. These findings agree closely with those reported in higher vertebrates, and suggest that metabolic activities, and possible secretory functions, of the pineal organ of fishes are synchronized to the light: dark cycle. Daily changes in these variables generally persisted in fish exposed to constant darkness for seven days, with the peaks in these rhythms coinciding closely with those observed in fish exposed to a light: dark cycle. In contrast, the rhythms in all variables were abolished in fish kept in continual light for seven days. Photoreceptor cells from fish exposed to continuous light had larger nucleoli and greater amounts of rough endoplasmic reticulum indicating a further effect of light on pineal metabolism in lower vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01252039
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Fine structure of the pineal organ in the troglobytic fish, Typhlichthyes subterraneous (Pisces: Amblyopsidae) (1978)
    Springer
    Cell & tissue research 195 (1978), S. 535-545 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ ; Troglobytic fish, Typhlichthyes subterraneous ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal organ of the blind, cave-dwelling fish, Typhlichthyes subterraneous, was examined with both light and electron microscopes. Like the eyes, the pineal in this troglobytic species was found to be regressed. Two cell types, photoreceptor and supportive cells, were described in the pineal epithelium. Although ganglion cells were not identified, small, unmyelinated nerve fibers were present. The photoreceptor cells had degenerated outer segments. Accordingly, it was suggested that the pineal in this species is not likely to function in photoreception. However, the presence of well developed Golgi bodies, clear and dense-cored vesicles, variable amounts of rough endoplasmic reticulum and glycogen particles indicated that both cell types are metabolically active and may play a role in secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233895
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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