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  • 1
    Electronic Resource
    Electronic Resource
    Neurotrophic effects of the pineal gland: Role of non-neuronal cells in co-cultures of the pineal gland and superior cervical ganglia (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 19 (1995), S. 0 
    Details
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The pineal gland (PG) is a source of several trophic factors. In this study, PG and superior cervical ganglia (SCG) from Sprague-Dawley neonates (1-day-old) were co-cultured to test the hypothesis that endogenous release of PG NGF (or an NGF-like cytokine) is sufficient to promote survival of SCG neurons. Neuronal density of SCG neurons was significantly enhanced when co-cultured with PG for 7 days compared to SCG cultured alone. SCG survival and neurite formation in PG co-cultures was less than in SCG treated with exogenous NGF (100 ng/ml). The neurotrophic effect of PG co-cultures was abolished when 1% anti-NGF was added to the medium. Co-cultures of SCG neurons with established 7-day PG cultures induced extensive SCG neurite formation within 24 hr compared to SCG co-cultured with 1-day PG cultures. This suggests that PG neurotrophic effects are due to PG non-neuronal cells (nnc) that proliferate to confluency by 7 days in culture. S-antigen-positive pinealocytes did not proliferate in culture. There was decreased SCG survival when neurons were seeded onto PG cultures that had been previously killed by drying, which suggests that the neurotrophic effects of nnc are not substrate-dependent. Immunocytochemical characterization of PG nnc revealed a heterogenous mixture of astrocytes, macrophage/ microglia, and fibroblasts. These findings support the hypothesis that NGF is actively secreted by PG and that nnc are the principal source of this neurotophin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-079X.1995.tb00169.x
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  • 2
    Electronic Resource
    Electronic Resource
    Regulation of synaptic ribbons in rat pineal gland explants by norepinephrine and sympathetic neurons in a co-culture model (1995)
    Springer
    Cell & tissue research 283 (1995), S. 59-66 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Synaptic ribbon ; Pineal gland ; Co-culture ; Norepinephrine ; Sympathetic ganglia ; Rat (Wistar ; Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The hypothesis that synaptic ribbons in the mammalian pinealocyte are influenced by adrenergic mechanisms was tested in the present study using a co-culture model of pineal glands and superior cervical ganglia from neonatal rats. Pineal gland explants survived and showed a high degree of differentiation when cultured for up to 30 days regardless of the presence or absence of superior cervical ganglia. Pineal glands also had neurotrophic properties promoting the survival and neurite extension from superior cervical ganglia. Synaptic ribbons were a common ultrastructural feature in all pineal cultures. There was a significant decline in synaptic ribbon numbers when co-cultured with superior cervical ganglia for both 7 and 30 days. A similar significant decrease in synaptic ribbon frequency was observed after treatment of pineal explants with norepinephrine (10−5 M) for both 7 and 30 days. These findings are consistent with the hypothesis that neural mechanisms play an important role in regulating synaptic ribbon numbers, at least during early development. The study also illustrates the utility of pineal gland-superior cervical ganglia co-cultures as a model for future investigations of neuron-target interactions in the pineal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050512
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  • 3
    Electronic Resource
    Electronic Resource
    Immunocytochemical and electron-microscopic characterization of macrophage/microglia cells and expression of class II major histocompatibility complex in the pineal gland of the rat (1993)
    Springer
    Cell & tissue research 272 (1993), S. 257-265 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Astrocytes ; Glial fibrillary acidic protein (GFAP) ; Macrophages ; Microglia ; MHC class II antigen ; Rat (various stains)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Interstitial cells in the pineal gland of the rat were characterized immunocytochemically using the monoclonal antibodies MRC OX-42 and ED1 for macrophages/microglia, and MRC OX-6, which recognizes major histocompatibility complex (MHC) class II antigen. A polyclonal antibody against GFAP was used to identify astrocytes. Cells immunopositive for OX-42 and/or ED1 were distributed throughout the gland; they extended processes primarily along the perivascular spaces and occasionally within the parenchyma of the gland. Ultrastructurally, these OX-42-positive cells were characterized by a nucleus with sparse heterochromatin and cytoplasmic vacuoles/lysosomes. Cells expressing MHC class II antigen had a distribution and morphology similar to OX-42-immunopositive cells, suggesting that pineal macrophages/microglia play a role as antigen-presenting cells. GFAP-positive astrocytes were concentrated at the proximal end of the pineal where the pineal stalk enters the gland. The occurrence of antigenpresenting cells in the circumventricular neuroendocrine gland has important functional implications as these cells may be mediators of neuroimmunomodulatory mechanisms, and involved in certain disease states such as autoimmune pinealitis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302731
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  • 4
    Electronic Resource
    Electronic Resource
    The morphology of canine lymphatic valves (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 202 (1982), S. 453-461 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The architecture of 60 valves from thoracic ducts and from renal hilar and mesenteric collecting lymph vessels of dogs were studied by scanning electron microscopy as well as by light and transmission electron microscopy. All of the valves seen in hilar and mesenteric lymph vessels and most of those studied in the thoracic duct were bicuspid. An occasional tricuspid and one monocuspid valve was seen in the thoracic duct. The semilunar cusps of the valves extended from the vessel wall, to which they were attached, towards the valve outlet where adjacent cusps fused. Coincident to the area of fusion was the formation of mesenteric-like folds or buttresses that anchored the cusps to the vessel wall. These folds extended 50-100 μm beyond the cusp margins on the outflow side of the valve. The attachments of the cusps, buttresses, and vessel wall to one another resulted in the formation of postvalvular sinuses, such that raised intraluminal pressure downstream to valve areas would distend the sinuses, causing leaflet apposition and hence valvular closure. The morphology of the valves was such that they were not considered to provide any significant impediment to the antegrade flow of lymph.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092020404
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  • 5
    Electronic Resource
    Electronic Resource
    Pinealocyte synaptic ribbons and neuroendocrine function (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 175-187 
    Details
    ISSN: 1059-910X
    Keywords: β-adrenergic receptor ; Development ; Isoproterenol ; Melatonin ; N-acetylserotonin ; Ribbon fields ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A comparative study of pinealocyte synaptic ribbons (SR) revealed two predominant populations exhibiting either a rod/ribbon shape (SRr) or a spherical/punctate shape (SRsp). Species-specific differences were found in the abundance of SR, the ratio of SRr/SRsp, and the occurrence of SR in ribbon fields. The close topographical relationship of SR to the plasma membrane and the numerical changes that occurred with changes in metabolism of the pinealocytes suggest that SR have important vesicle-mediated interactions with the cell membrane. Experiments designed to clarify the relationship between SR and pineal neuroendocrine function revealed a positive correlation between SR numbers and indole intermediates during pineal development in the rat, and increased SR frequency after denervation of the rat pineal gland or administration of the β-adrenergic agonist, isoproterenol. These data are consistent with the hypothesis that SR function is linked to receptor mechanisms regulating indoleamine production in the pineal gland. © 1992 Wiley-Liss, Inc.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070210302
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructure and organization of circumventricular organs and endolymphatic tubules in the treefrog, Hyla versicolor (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 197-208 
    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 anatomical relationship of the paraphysis, anterior choroid plexus, and endolymphatic tubules of Hyla versicolor suggest that these structures may act as a functional unit to regulate composition of the cerebrospinal fluid (CSF). Ependymal cells of both the paraphysis and the choroid plexus exhibit ultrastructural features (an extensive microvillar border, large intercellular spaces containing an amorphous material, and apically located mitochondria) which indicate active exchange between the blood and CSF. Mast cells (which may play a role in regulating vascular permeability) also occur on the brush border. The tubules of the endolymphatic sacs were found to lie in close relation with the dorsal portion of the paraphysis. The endolymphatic organ is known to play a role in systemic buffering during respiratory acidosis and may influence Na/K fluxes via calcium release. The association of the paraphysis with the endolymphatic tubules may therefore represent an important mechanism for ion regulation in the CSF of amphibians. The ultrastructure of the pineal organ agrees with descriptions for other species. No pineal stalk was present. Photoreceptor inner and outer segments project into a central lumen continuous with the third ventricle. Outer segments show signs of disorganization. Photoreceptor/neural dendrite contacts involve synaptic ribbons and conventional synapses.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040208
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