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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of l-glutamate on the adrenergic-stimulated release of melatonin in the rat pineal gland was examined using an in vitro perfusion system. l-Glutamate by itself had no effect on melatonin secretion whereas l-glutamate administered prior to (–)-isoproterenol (β-adrenergic agonist) and l-phenylephrine (α-adrenergic agonist) inhibited melatonin production by 42%. l-Glutamate did not inhibit melatonin secretion when glands were stimulated with (–)-isoproterenol alone. d-Glutamate, as well as the l-glutamate agonists kainate, N-methyl-d-aspartate, quisqualate, and trans-1-aminocyclopentane-1, 3-dicarboxylic acid, had no effect on the (–)-isoproterenol-and l-phenylephrine-stimulated secretion of melatonin, which suggests that the inhibitory effects of glutamate are not mediated via any of the known glutamate receptor subtypes. The possibility that l-glutamate may be converted to another neuroactive compound (GABA) prior to the addition of (–)-isoproterenol and l-phenylephrine is suggested by the observation that simultaneous administration of l-glutamate with (–)-isoproterenol and l-phenylephrine did not inhibit melatonin production.
    Type of Medium: Electronic Resource
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  • 2
    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
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 1 (1984), S. 0 
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 23 (1997), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Graham DJ, McNulty JA. A note on the time dependence of pineal gland research publications. J. Pineal Res. 1997; 23:59–62. ©Munksgaard, Copenhagen〈section xml:id="abs1-1"〉〈title type="main"〉AbstractCounts of the number of publication titles containing the search truncation “pinea*” were compiled via Current Contentsover the time period 1978–1994. These counts and their time dependence were examined for autocorrelations and frequency spectral components. Such analyses were carried out irrespective of either author, research laboratory, funding, or other factors. Interestingly, the results show the research publication rate in pineal studies to be linked to community history. In particular, the interactions affecting output among community members operate on a few characteristic time scales ranging from one to several years.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 14 (1993), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Glutamate, an excitatory neurotransmitter/neuromodulator involved in cell-to-cell communication within the central nervous system, is now believed to play a role in neuroendocrine function. In this study we describe a single, saturable, stereospecific, and temperature-, time-, and pH-dependent binding site for glutamate in the pineal gland of the rat (Kd= 612 ± 23 nM, Bmax= 3.17 ± 0.33 pmol/mg protein). After removal of the sympathetic innervation to the pineal gland, [3H]glutamate binding displayed a higher apparent affinity (Kd= 412 ± 28 nM) (P 〈 0.05) without a change in binding site number (Bmax= 3.60 ± 0.24 pmol/mg protein). No difference in [3H]glutamate binding site number was observed in pineal glands obtained from animals sacrificed during the middle of the light and dark periods. These data suggest a possible modulatory role for a glutamate binding site in pineal gland function.
    Type of Medium: Electronic Resource
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  • 6
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    Unknown
    New York : Periodicals Archive Online (PAO)
    Journal of Memory and Language. 4:5 (1965:Oct.) 430 
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Annals of vascular surgery 6 (1992), S. 153-159 
    ISSN: 1615-5947
    Keywords: Vascular clamping ; vessel wall histology ; mechanical properties of arteries ; histology ; occluders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mechanical properties of arteries, along with the histologic and scanning electron microscopy characteristics of the nonatherosclerotic canine arteries, were investigated six months after vascular clamping. Different vessel clamps were applied to 73 sites on the carotid and femoral arteries in five anesthetized dogs. Each clamp was applied for 30 minutes with (a) sufficient force to just occlude blood flow or (b) as tightly as the clamp could be placed. After six months the vessels were excised, filled with barium sulfate suspension, and pressurized in 25 mmHg steps up to 150 mmHg. High resolution contact radiographs were taken at each pressure. These were magnified 35x and measured. Scanning electron microscopy and conventional histology disclosed that the clamped sites exhibited serrated clamp “tracks” in the intima, intimal hyperplasia, and, in a few cases, fractured elastic lamellae. These histologic changes were seen more frequently in the femoral artery than in the carotid artery (p〈.01). The mechanical properties, as determined from radiographic measurements, demonstrated that, for all types of clamps, the luminal diameter, pressure-diameter relationship, and compliance of the clamped vessels were not significantly different from nonclamped control regions (ANOVA). These studies demonstrate that careful application of clamps to nonatherosclerotic arteries produces persistent morphologic changes, but these are not associated with altered mechanical properties of the vessel wall.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Synaptic ribbon ; Pinealocyte ; Ovariectomy ; Estradiol ; Rhesus monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pinealocytes of rhesus monkeys that had been ovariectomized and given intramuscular injections of 250 μg estradiol-benzoate for 3 consecutive days tended to have more synaptic ribbons (SR) and exhibited a significantly greater size of ribbon fields (RF) compared to untreated animals. These data are consistent with hypotheses that pinealocyte function in primates is altered by hormonal imbalances and that the SR participates in this response. RF were positioned in various parts of the cytoplasm and along the plasma membrane. Participation of SR in direct cell-to-cell contacts was suggested by the formation of densities along the plasma membrane. It is postulated that large RF serve as storage organelles and that the formation of RF results from division of pre-existing SR in each field. Reconstructions made from serial thin sections revealed that profiles of RF comprised separate SR that were not folded and sectioned along various planes.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 207 (1980), S. 109-121 
    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
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 210 (1980), S. 249-256 
    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
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