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  • 1
    Electronic Resource
    Electronic Resource
    Responses of Synaptic Ribbons in Pineal Photoreceptors Under Normal and Experimental Lighting Conditions (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 1 (1984), S. 0 
    Details
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The size of synaptic ribbons (SR) in photoreceptor cells of the goldfish pineal organ was quantified over 24-h light:dark cycles of long (16:8) and short (10:14) photoperiods during summer and winter months, respectively. The amplitude of both rhythms was similar with peak values occurring toward the latter part of the photophase or early dark. When fish were entrained to the long photoperiod and exposed to continual light, SR size continued to increase during the expected dark time. The effect of extending the photoperiod into the expected dark time was diminished when fish were entrained to a short photoperiod and presented with 6 h of darkness at the end of the 24-h period. The size increase in response to environmental lighting is believed to reflect a greater demand for either vesicle attachment sites or neurotransmitter storage sites since vesicles (neurotransmitter) have been hypothesized to accumulate in the synaptic pedicles during inhibition by light. From a comparative standpoint it is noteworthy that synaptic ribbons (vesicle-crowned rods) in mammals react in a similar manner to both normal and experimental lighting conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-079X.1984.tb00205.x
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  • 2
    Electronic Resource
    Electronic Resource
    Organ culture of the goldfish pineal body (1984)
    Springer
    Cell & tissue research 238 (1984), S. 565-575 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ teleost ; Tissue culture ; Ultrastructure ; Indoles ; High performance liquid chromatography (HPLC)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure and biochemistry of the goldfish pineal organ were examined in expiants cultured for 1, 3, and 6 days. All four cell types (photoreceptor, supportive, ganglion, phagocytic) were identified; they exhibited many of the characteristics of these cells in vivo. Exceptions included a gradual disorganization of the outer segments and reduction of synaptic ribbons in photoreceptors with time in culture. In addition, there was a marked proliferation of endoplasmic reticulum in both photoreceptor and supportive cells. The indoles 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid, 5-methoxytryptophol, and melatonin were separated in expiants by high performance liquid chromatography using electrochemical detection. Serotonin levels could be depleted by p-chlorophenylalanine and elevated by nialamide or by adding 5-hydroxytryptophan to the culture medium. These findings suggest that organ culture may be a useful model for study of regulatory processes related to the photoneuroendocrine functions of the teleost pineal organ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219873
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The morphology of dermal chromatophores in the infrared-reflecting glass-frog Centrolenella fleischmanni (1980)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 163 (1980), S. 37-44 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology and organization of chromatophores in the neotropical glass-frog, Centrolenella fleischmanni (family Centrolenidae), were studied with both light and electron microscopes. Four types of pigment cells are described in the dorsal skin. The fine structure of two chromatophores corresponds to the typical amphibian xanthophore and iridophore; one is similar to the unusual melanophore found in phyllomedusine hylids; the fourth cell type is unlike any chromatophore previously described. Pigment granules in the unusual chromatophore are moderately electron-dense and have an irregular shape, suggesting a fluid composition. This pigment appears to be laid down in organelles similar in appearance to pterinosomes. The organization of pigment cells in this species differs from that of other green, leaf-sitting frogs in that there are few discrete groups resembling “dermal chromatophore units.” It is suggested that the unusual new pigment cell contributes significantly to the overall green color of C. fleischmanni.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051630106
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  • 4
    Electronic Resource
    Electronic Resource
    The pineal region in the opossum, Didelphis virginiana (1980)
    Springer
    Cell & tissue research 207 (1980), S. 109-121 
    Details
    ISSN: 1432-0878
    Keywords: Pineal region ; Opossum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pineal region of the opossum, Didelphis virginiana, two types of cells predominate: 1) pinealocytes, and 2) fibrous astrocytes. Pinealocytes are characterized by the presence of prominent Golgi bodies, numerous clear and dense-cored vesicles, sensory cilia (9+0), vesicle-crowned rods, and condensation of a material that was always associated with the rough endoplasmic reticulum. In addition, two other cell types are occasionally seen. These include 1) neuron-like cells, and 2) darker staining cells of unknown identity. The endoplasmic reticulum of the darker staining cells is typically expanded and filled with an amorphous substance. Although the pineal region is small in size, the present findings suggest that pinealocytes in this species are metabolically active cells displaying a secretory function. Moreover, the presence of sensory cilia (9+0) and vesicle-crowned rods indicates that pinealocytes of the opossum are phylogenetically related to the photoreceptor cells found in the pineal organ of lower vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239333
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  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructural observations on synaptic ribbons in the pineal organ of the goldfish (1980)
    Springer
    Cell & tissue research 210 (1980), S. 249-256 
    Details
    ISSN: 1432-0878
    Keywords: Synaptic ribbons ; Pineal organ ; Goldfish ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptic ribbons in the pineal organ of the goldfish were examined electron microscopically with particular attention to their topography. These structures were formed of parallel membranes, which were poorly preserved with OsO4 fixation and could be extracted from thin sections with pronase indicating their proteinaceous nature. Synaptic ribbons were closely apposed to the plasma membrane bordering dendrites of ganglion cells, but were also related to processes of both photoreceptor and supportive cells. Their close proximity to invaginations of the plasma membrane and portions of the endoplasmic reticulum suggest that they are involved in the turnover of cytoplasmic membranes. Tubular and spherical organelles of unknown function are also described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237613
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Synaptic ribbons in the pineal organ of the goldfish: Circadian rhythmicity and the effects of constant light and constant darkness (1981)
    Springer
    Cell & tissue research 215 (1981), S. 491-497 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ ; Synaptic ribbons ; Circadian rhythm ; Constant light ; Constant darkness ; Goldfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptic ribbons in photoreceptor cells of the goldfish pineal organ undergo significant daily changes in their length, distance from the plasma membrane, and number per unit area of pineal end-vesicle. The rhythms persist in fish exposed to constant darkness. Constant light abolishes the rhythms in length and distance of synaptic ribbons from the plasmalemma, but has little effect on numerical changes over a 24-h cycle. These findings suggest that synaptic ribbons in the pineal organ of lower vertebrates might be useful as indicators of metabolic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233525
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  • 7
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for seasonal changes in pinealocytes of the 13-lined ground squirrel, spermophilus tridecemlineatus: A qualitative and quantitative study (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 196 (1980), S. 387-400 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fine structure of pinealocytes in the hibernating ground squirrel, Spermophilus tridecemlineatus, was found to vary both qualitatively and quantitatively according to the season in which the animals were sacrificed. Ultrastructural features of pinealocytes from fall (prehibernation) and winter (hibernation) periods, when the animals were sexually quiescent, included: (1) arrangement of the endoplasmic reticulum into flattened stacks or concentric rings (formations which have been implicated in antigonadotropic activity of the pineal); (2) condensations of a fine granular material; and (3) dilation of the cisternae of the endoplasmic reticulum and Golgi bodies with an increased number of Golgi associated vesicles. Moreover, there was an apparent increase in the number of dense-cored vesicles and microtubules in pinealocytes of winter animals. These findings indicate that a circannual rhythm in pinealocyte ultrastructure occurs in this species and further suggest that cellular activity is seasonal.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091960404
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  • 8
    Electronic Resource
    Electronic Resource
    Morphometric analysis of the pineal complex of the golden hamster over a 24-hour light: Dark cycle: II. The deep pineal in untreated and optically enucleated animals (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 171 (1984), S. 369-376 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The deep pineal gland of golden hamsters was morphometrically analyzed and quantitatively compared with the superficial pineal under a 14:10 lighting regime and following blinding. The deep pineal comprised 6-10% of the total pineal parenchymal tissue. Pinealocytes of the deep gland were smaller than the cells of the superficial pineal and showed a greater percent volume of Golgi bodies, rough endoplasmic reticulum, and dense-cored vesicles. Twenty-four-hour rhythms in nucleoli and Golgi bodies were found in deep pinealocytes. These rhythms were out of phase with comparable rhythms in the superficial pineal gland, suggesting that distinct subpopulations of pinealocytes are present within the respective parts. Blinding resulted in decreased nuclear and nucleolar volume, while the amount of smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense-cored vesicles increased significantly. Marginal increases were seen in mitochondria and lipid droplets. The greater abundance of those organelles involved in synthesis and secretion suggests enhanced cellular activity after blinding. Many of the morphological responses are similar to alterations in the pinealocytes of the superficial pineal following optic enucleation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001710403
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  • 9
    Electronic Resource
    Electronic Resource
    Morphometric analysis of the pineal complex of the golden hamster over a 24-hour light: Dark cycle: I. The superficial pineal in untreated and optically enucleated animals (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 171 (1984), S. 359-368 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Morphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was conducted at both the light and electron microscopic level. The volume of the superficial gland was estimated to be 151 × 106 μm3, comprising 90-94% of the total pineal parenchymal tissue. Analysis of structural rhythms in animals maintained under a 14:10 L:D cycle showed significant 24-hr variations in values for pinealocyte nuclei, nucleoli, rough and smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense-cored vesicles. Peak values for these structures generally occurred at the light:dark interface. These results provide morphological correlates for known rhythmic variations in the synthesis of pineal-gland products. Superficial pineals examined 8 weeks following optic enucleation exhibited a decrease in the volume of pinealocyte nuclei and cytoplasm, while nucleolar size and the amounts of smooth and rough endoplasmic reticulum, Golgi bodies, dense bodies and dense-cored vesicles were enhanced. The latter changes are interpreted as indications of increased synthetic activity by the superficial pineal gland in response to light deprivation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001710402
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