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  • 1
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system of the wild carp, Cyprinus carpio L. (1984)
    Springer
    Cell & tissue research 237 (1984), S. 139-147 
    Details
    ISSN: 1432-0878
    Keywords: Posterior neurohypophysis ; Pars intermedia complex ; Light, fluorescence and electron microscopy ; Carp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The posterior neurohypophysis (PNH)-pars intermedia complex of the wild and pond carp, Cyprinus carpio L., has been studied by light, fluorescence and electron microscopy. “Gomori-positive” neurosecretory fibres are abundant in the main trunk of the neurohypophysis as well as its roots penetrating the pars intermedia. Terminals of these fibres are in contact with capillaries of the general circulation and with glandular cells of the pars intermedia. Monoaminergic fibres with a weak green fluorescence, somewhat increasing after injection of nialamide into the pond carp, have largely the same distribution. Three types of neurosecretory fibres and their terminals have been recognized in the PNH-pars intermedia complex. Types-A1 and -A2 fibres, containing granules of 140–180 nm and 100–160 nm in diameter respectively, are peptidergic “Gomori-positive”. Type-A2 fibres predominate in the PNH. The least frequent monoaminergic type-B fibres have granules of 60–100 nm in diameter. Numerous peptidergic and few monoaminergic neurosecretory terminals make contact with the capillaries located within the roots of the PNH as well as at the border between them and the pars intermedia. Both peptidergic and monoaminergic terminals make direct synaptoid contacts with the gland cells or end close to connective tissue septa, basal lamina or pituicytes. The PAS-positive gland cells and to a lesser degree the leadhaematoxylin-positive gland cells show these relationships with neurosecretory terminals. The question concerning the mode of interaction between peptidergic and monoaminergic structures in the dual control of the gland cells of the pars intermedia of teleosts is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229209
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  • 2
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system of the lamprey, Lampetra fluviatilis L. (1979)
    Springer
    Cell & tissue research 204 (1979), S. 319-331 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Lamprey ; Regulation of pars distalis ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The proximal neurosecretory contact region (PNCR) of the lamprey, a homologue of the median eminence of tetrapods, was studied by light, fluorescence and electron microscopy. Paraldehyde fuchsin-positive neurosecretory fibers are seen mainly in the central part of the rostral subdivision of the PNCR. The Falck-Hillarp technique reveals a weak, mainly diffuse yellow-green fluorescence in the PNCR. The ultrastructure of the tanycyte layer of the PNCR is very similar to that in the neurohypophysis of the same species, although the funnel-shaped protrusions of the third ventricle in the rostral part of the PNCR are more frequent than in the neurohypophysis. Peptidergic A1 and A2 neurosecretory fibers are characterized by neurosecretory granules of 120– 200 nm and 100–150 nm in diameter, respectively. Monoaminergic B type fibers contain granules 80–100 nm in diameter. Neurosecretory terminals and the vascular endfeet of tanycytes make contact with the basement membrane of the avascular connective tissue layer separating the PNCR from the hypophysial pars distalis. It is suggested that both peptide and monoamine neurohormones diffuse through the thick connective tissue septa into the underlying blood vessels which supply the pars distalis and thus affect the function of its glandular cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234643
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  • 3
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system of the wild carp, Cyprinus carpio L. (1985)
    Springer
    Cell & tissue research 239 (1985), S. 211-218 
    Details
    ISSN: 1432-0878
    Keywords: Anterior neurohypophysis-pars distalis complex ; Light, fluorescence and electron microscopy ; Carp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anterior neurohypophysis (ANH)-pars distalis complex of the carp, Cyprinus carpio L., has been analysed by combined light, fluorescence and electron microscopy. Only few “Gomori-positive” fibres are seen in the caudal and especially in the rostral part of the ANH, where the false “Gomori-positive” fibres predominate. Monoamine fluorescence shows the same distribution although it is extremely weak and only slightly increases after nialamide treatment. Four types of neurosecretory fibres and their terminals have been recognized in each part of the ANH. The sizes of neurosecretory granules contained in peptidergic A1- and A2-type fibres terminating in the rostral (120–220 nm and 60–140 nm) and caudal (120–160 nm and 90–120 nm) parts of the ANH differ. Monoaminergic B and B1-type fibres have rounded (60–100 nm) or elongated (40×80 nm) granules, respectively. Some neurosecretory terminals (NST) of different types make contact with the capillaries located within the ANH roots as well as at the border between the latter and the pars distalis. Direct synaptoid axo-glandular contacts are very limited, and most neurosecretory fibres end close to continuous connective tissue septa separating the nervous tissue from the glandular cells of the rostral and caudal pars distalis. The question of the mode of the neuro-glandular relations in the complex ANH-pars distalis of teleosts is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214921
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative radioautographic light and electron microscopic analysis of the localization of monoamines in the median eminence of the rat (1979)
    Springer
    Cell & tissue research 204 (1979), S. 305-317 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Serotonin ; Quantitative light and electron microscopic radioautography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Serotonin containing structures in the median eminence of the rat have been studied by quantitative light and electron microscopic radioautography following intraventricular infusion of tritiated 5-hydroxytryptophan. One hour after injection of the tracer the highest density of silver grains was recorded in the ependymal and external zones, especially in the lateral palisade zone. The proportion of labelled neurosecretory terminals was also larger in the lateral palisade zone (29%) as compared with the medial palisade zone (13%), although the mean number of developed silver grains per one terminal was higher in the latter. On the average, 16% of neurosecretory terminals sequestered radiolabelled 5-hydroxytryptophan in the external zone of the rat median eminence. It is suggested that serotonin, like catecholamines, is discharged from neurosecretory terminals localized in the external zone and via the portal circulation affects the function of the anterior pituitary. The sites of origin of serotoninergic structures of the median eminence as well as the possible role of monoamine (catecholamine and indolamine) neurohormones in a dual peptidergic and monoaminergic control of anterior pituitary functions are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234642
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  • 5
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system of the lamprey, Lampetra fluviatilis L. (1979)
    Springer
    Cell & tissue research 204 (1979), S. 333-342 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Neurohypophysis ; Lamprey ; Monoaminergic structures ; Light and electron microscopic radioautography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of monoaminergic structures was studied in the proximal neurosecretory contact region and neurohypophysis of the lamprey by light and electron microscopic radioautography. Only weak radioautographic reactions were found in the proximal neurosecretory contact region 1 h after injection of 3H-dopamine. High-resolution radioautography revealed some labeled neurosecretory terminals mainly in contact with the basement membrane of the connective tissue layer separating the proximal neurosecretory contact region from the hypophysial pars distalis. The number of silver grains as well as the number of neurosecretory terminals marked by the presence of labeled dopamine was much higher in the neurohypophysis of the same species. In the latter, labeled neurosecretory terminals were found in contact with the connective tissue layer containing blood vessels of the general circulation. Some neurosecretory terminals make synaptoid contacts with tanycyte perikarya and their basal processes. According to their ultrastructure and the size of their granules, the labeled neurosecretory terminals are identical with the B type terminals described in both neurohemal regions (transmission electron microscopy). No labeled neurosecretory terminals were observed in the proximal neurosecretory contact region and the neurohypophysis of lampreys treated with the serotonin precursor, 3H-5-hydroxytryptophan.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234644
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  • 6
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system in acipenseridae (1979)
    Springer
    Cell & tissue research 203 (1979), S. 311-320 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Acipenseridae ; Ultrastructure ; Quantitative analysis ; Spawning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The percentage of peptidergic (A1 and A2) and adrenergic (B) neurosecretory terminals was studied in the neurohypophysis of sexually mature female sturgeons. Neurosecretory terminals of the A2 type prevail in the neurohypophysis, whereas A1 and B terminals are rare. The activity of these types of terminals was established (1) during upstream migration, (2) shortly after spawning, and (3) three to six weeks after spawning. Terminals of B type are the most active elements during all the periods studied. These elements become strongly activated in sturgeons during upstream migration, i.e., earlier than the peptidergic neurosecretory terminals. Peptidergic terminals, especially elements of type A2, become synchronously and strongly activated in fish shortly after spawning. In the late postspawning period neurosecretory terminals of all three types become synchronously inactive, persisting in a quiescent state in comparison to the two previous periods. The appearance of neurosecretory material discharged into the intercellular clefts by exocytosis correlates on the whole with the activity level of the A1 and A2 terminals in each individual studied. A functional correlation exists between the activity of the peptidergic and adrenergic neurosecretory terminals in the neurohypophysis. The data obtained are discussed with reference to a concept regarding spawning in some fish species as a physiological stress (Polenov et al., 1976). A possible dual control (peptide and monoamine neurohormones) over the function of visceral organs and glandular cells of the intermediate lobe of the hypophysis is also suggested (Polenov, 1970, 1975, 1978; Polenov and Belenky, 1973).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237245
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  • 7
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system of the frog Rana temporaria (1986)
    Springer
    Cell & tissue research 243 (1986), S. 649-654 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Peptidergic projections ; Aminergic projections ; Electron microscopy ; Autoradiography ; Frog (Rana temporaria)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The median eminence (ME) of the adult frog, Rana temporaria, was studied by means of electron microscopy including quantitative electron-microscopic autoradiography. In frogs captured in May and June numerous peptidergic neurosecretory fibres extending via the internal zone to the pars nervosa display large swellings containing few granules, mitochondria, neurotubules and cisternae of the smooth endoplasmic reticulum. In addition, few secretory globules up to 1.5 μm in diameter occur in these varicosities. In animals collected during the autumn period many of these neurosecretory swellings filled with neurosecretory granules and polymorphic inclusions resemble Herring bodies. Three types of granule-containing neurosecretory fibres were observed in the external zone (EZ) of the ME of adult R. temporaria. Peptidergic A1- and A2-type fibres are characterized by granules 150–220 nm and 100–160 nm in diameter, respectively. Monoaminergic fibres of type B with granules approximately 100 nm in diameter represent ∼ 50% of all neurosecretory elements in the EZ of the frog ME; ∼12% of the total number of granule-bearing axons in the EZ actively taking up radiolabelled 5-hydroxytryptophan are thought to be serotoninergic terminals. Neurosecretory terminals of all types and glial vascular endfeet establish direct contacts with the perivascular space of the primary portal capillaries. Some neurosecretory terminals are separated from the lumen of the third ventricle by a thin cytoplasmic lamella of tanycytes. The possible physiological significance of this structural pattern is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218074
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  • 8
    Electronic Resource
    Electronic Resource
    The hypothalamo-hypophysial system of hypophysectomized rats (1981)
    Springer
    Cell & tissue research 218 (1981), S. 607-622 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysectomy ; Median eminence ; Light and electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The median eminence (ME) of hypophysectomized rats was studied by means of light and electron microscopy. Paraldehyde-fuchsin (PAF)-positive material is seen in the external zone (EZ) of the ME 2–5 days after the operation. Its amount gradually increases especially in the caudal part of the ME during the following few days. Some PAF-positive fibers make contact with the subependymally located blood capillaries. In the most caudal region of the recessus infundibuli they penetrate into the third ventricle. PAF-positive material decreases markedly from the ME of rats two months after hypophysectomy and exposure to a 1% salt load. Fibers of types A1, A2 and B containing granules of 120–220 nm, 100–150 nm and 80–100 nm in diameter, respectively, are seen in the EZ of the ME in hypophysectomized rats, although almost exclusively A2- and B-type structures make contact with the primary portal capillaries in intact animals. All types of neurosecretory fibers establish contact with the subependymal nonfenestrated blood capillaries and penetrate the recessus infundibuli. Some neurosecretory terminals of different types make direct contact with the glandular cells of the pars tuberalis or are separated from them by a thin basal lamina. It is assumed that mainly neurosecretory fibers of types A2 and B are permanently connected with the primary portal capillaries in the EZ of the ME in intact mammals, while the overwhelming majority of fibers of A1-type shows ingrowth during the course of postoperative reparation. The possible physiological significance of the described changes is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210119
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative radioautographic light and electron microscopic analysis of the localization of monoamines in the median eminence of the rat (1979)
    Springer
    Cell & tissue research 203 (1979), S. 469-485 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Catecholamines ; Quantitative light and electron microscopic radioautography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By means of light and electron microscopic radioautography a quantitative study of the regional distribution of catecholamines in the median eminence of the rat was carried out. One hour after intraventricular injection of 3H-dopamine the highest radioautographic reaction was recorded in the external zone, especially in the lateral palisade zone where many neurosecretory terminals are separated from the basal lamina of the portal pericapillary space by a glial “cuff”. This area showed the highest percentage (52%) of labelled catecholamine containing neurosecretory terminals as well as the maximal silver grain density per one terminal. In the medial palisade zone where direct neurovascular contacts with the capillary loops prevail, only 27 per cent of neurosecretory terminals were found to harbour tritiated dopamine. On the average 35 per cent of neurosecretory terminals in the median eminence of the rat contain catecholamines (both dopamine and noradrenaline). Pretreatment of animals with reserpine strongly reduced the binding of the label. Per cent of labelled neurosecretory terminals as well as grain density over terminals were decreased in both the medial and lateral palisade zones, although to a lesser degree in the latter. The site of origin of catecholamine fibers as well as the mode of catecholamine action at the level of the median eminence are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233275
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