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  • 1
    Electronic Resource
    Electronic Resource
    A new histo-and cytochemical method for demonstration of cyclic 3′, 5′-nucleotide phosphodiesterase activity in retinal rod photoreceptor cells of the rat (1984)
    Springer
    Histochemistry and cell biology 81 (1984), S. 445-451 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic 3′, 5′-mononucleotide phosphodiesterase (cyclic nucleotide PDEase) activity was studied histo-and cytochemically in the retinal rod photoreceptor cells of the rat by means of a newly developed technique utilizing the intrinsic 5′ nucleotidase activity instead of an exogenous 5′ nucleotidase source (snake venom). Cyclic GMP and cyclic AMP were used as substrates. When cyclic GMP was used as a substrate, the intense activity of phosphodiesterase (PDEase) was distributed over the entire rod outer segments; reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A slight reaction was also observed on the plasmalemma of the inner segments. However, no precipitate was found in the perinuclear and synaptic regions of the rod photoreceptors. In contrast, when cyclic AMP was utilized as a substrate, a moderate reaction was seen in the synaptic region of the plexiform layer. The intensity of the reaction in the outer segments was much reduced in comparison to the results with cyclic GMP. The enzyme activity was almost completely inhibited by 2 mM 3-isobutyl-1-methylxanthine (IBMX) or 2 mM theophylline, which were potent inhibitors of PDEase. To confirm the propriety of our new cytochemical method, the localization of 5′ nucleotidase was also studied utilizing 5′ AMP or 5′ GMP as substrates. In contrast to the activity of cyclic nucleotide PDEase, the activity of 5′ nucleotidase was distributed on all membranes of the photoreceptors from the synaptic outer plexiform layer to the tip of outer segments. After inhibition of the intrinsic 5′ nucleotidase activity with the use of 1 mM Ni-ions or 10 mM NaF no demonstration of cyclic nucleotide PDEase activity was possible; the existence of intrinsic 5′ nucleotidase activity is necessary for the release of free phosphateions from 5′ AMP (5′ GMP), which are a prerequisite for the histochemical reaction. For comparison, some sections were incubated with the conventional cyclic nucleotide PDEase incubation medium containing snake venom from Ophiophagus hannah. With this conventional method, morphological preservation was extremely poor, and moreover, the reaction itself was weaker than that with the presently described method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00489748
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  • 2
    Electronic Resource
    Electronic Resource
    Histochemical and cytochemical demonstration of Ca++-ATPase activity in the stellate cells of the adenohypophysis of the guinea pig (1985)
    Springer
    Histochemistry and cell biology 83 (1985), S. 195-200 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The histo- and cytochemical localization of Ca++-ATPase activity in the adenohypophysis of the guinea pig was studied utilizing a newly developed method (Ando et al. 1981). An intense reaction was observed in the wall of the blood vessels and between non-secretory cells (stellate cells) and endocrine cells of the pars distalis. Under the electron microscope the Ca++-ATPase reaction product was located extracellularly in relation to the plasmalemma of the stellate cells. This reaction was dependent on Ca++ and the substrate, ATP, and reduced by the addition of 0,1 mM quercetin to the standard incubation medium. Preheating of the sections before incubation completely inhibited the enzyme activity. When Mg++ in different concentrations were substituted for Ca++ in the incubation medium the reaction was always reduced. Both Ca++ and Mg++ in the incubation medium also reduced the reaction. The plasmalemma of the endocrine cells contains no demonstrable amount of Ca++-ATPase activity. The function of the Ca++-ATPase activity is discussed in relation to the regulation of the extracellular Ca++ concentration which seems to be important with respect not only to the secretory process of the endocrine cells but also to the metabolism of the adenohypophysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00953983
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastruktur des pinealen Sinnesapparates bei einigen Pipidae und Discoglossidae (1968)
    Springer
    Cell & tissue research 92 (1968), S. 452-476 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Der Pinealkomplex der Anuren ist ein spezialisiertes Organ. Dafür sprechen sowohl physiologische Befunde als auch der histologische Aufbau, die Nervenverbindung mit dem Gehirn und die starke Blutversorgung. Degenerationszeichen sind nur an einem Teil der Rezeptorenaußenglieder zu beobachten; daneben finden sich stets voll differenzierte Sinneszellen. An der Epiphysis cerebri einiger stammesgeschichtlich bemerkenswerter Anurenformen (Pipidae: Xenopus laevis, Hymenochirus boettgeri; Discoglossidae: Bombina bombina) wird gezeigt, daß die durch Invaginationen des Plasmalemms entstandenen Außengliedstrukturen (Plättchen) nicht wie bei den Stäbchen und Zapfen der Lateralaugen auf einen bestimmten Durchmesser festgelegt sind. Aus ursprünglich zapfenähnlichen Formen entstehen durch tiefere Plasmalemmeinstülpungen Außenglieder, deren Lamellen das Innenglied kapuzenförmig überdecken. Bin weiteres Fortschreiten des Invaginationsprozesses führt zu unregelmäßigen Auf- und Abfaltungen des Außengliedes; an solchen Außengliedern treten Degenerationszeichen auf. Es werden zwei verschiedene Ablaufsformen der Degeneration beschrieben: 1. Membrankomplexe werden am distalen Pol abgestoßen; 2. Ein lytischer Abbau erfolgt von der Basis her. Diese Befunde werden unter Berücksichtigung energetischer Aspekte diskutiert. — Die Stützzellen sind offenbar zu trophischen und phagocytotischen Leistungen befähigt. Sie enthalten zahlreiche Myeloidkörper, deren Punktion ungeklärt ist. In der plexiformen Zone der Epiphysis cerebri sind neben Synapsen, die von basalen Sinneszellfortsätzen und Dendriten der Ganglienzellen gebildet werden, markhaltige und marklose Nervenfasern nachweisbar. Die marklosen Nervenfasern enthalten elektronendichte Granula. Vereinzelte elektronendichte Granula finden sich neben zahlreichen 500 Å großen Vesikeln auch in den basalen Sinneszellausläufern; die Bedeutung dieser Zelleinschlüsse ist noch ungeklärt.
    Notes: Summary The pineal complex of the anura is a specialized organ as demonstrated with physiological and histological methods. It shows a connection with the brain by nerve fibers and an extensive vascularization. Physiological degeneration is seen only in a part of the outer segments of the sensory cells. In the pineal organ of several phylogenetically remarkable anuran species (Pipidae: Xenopus laevis, Hymenochirus boettgeri; Discoglossidae: Bombina bombina) the flattened sacs of the outer segment form more irregular arrangements than in the lateral eye receptors and overlap the inner segment. When the invaginations become more complex, irregular outer segments are frequently observed. In such outer segments degeneration occurs in either of two ways: 1. The membrane complexes are discarded from the apex, 2. lysis starts in the basal portion. These observations are discussed considering the energyutilization aspects. — The supporting cells seem to have trophic and phagocytic functions. These cells contain also myeloid bodies with unknown function. — The plexiform region of the pineal organ contains, in addition to the basal processes of the receptor cells and the dendrites of the nerve cells, also myelinated and unmyelinated nerve fibers. The unmyelinated fibers contain dense-core granules. Besides many vesicles with a diameter of 500 Å, there are also some dense-core granules in the basal processes of the receptor cells; the functional role of these inclusions is still open to discussion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455602
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  • 4
    Electronic Resource
    Electronic Resource
    Granulierte marklose Nervenfasern in der Epiphysenregion von Anuren (1968)
    Springer
    Cell & tissue research 90 (1968), S. 389-402 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In der ganzen Epiphysenregion der Anuren, vor allem aber in perivaskulärer Anordnung, sind marklose Nervenfasern zu beobachten. Ein Teil dieser Fasern enthält Vesikel vom Typ synaptischer Bläschen sowie elektronendichte Granula mit einem Durchmesser von 500–1000 bzw. 2000 Å. Die granulahaltigen Fasern dringen vereinzelt bis in die synaptischen Regionen der Epiphyse vor. Es wird darauf hingewiesen, daß eine Verletzung dieses ausgedehnten Fasersystems bei Epiphysen-Exstirpationen und die Verunreinigung des Epiphysenmaterials mit benachbarten Gewebspartien bei der Gewinnung von Epiphysen-Extrakten zu falschen Schlüssen über die Funktion der Anuren-Epiphyse führen können.
    Notes: Summary The anuran pineal region, which includes the connective tissue capsule of the pineal organ and adjacent parts of brain, shows many unmyelinated nerve fibers. Most of these fibers have a perivascular location. Many of the fibers contain inclusions resembling synaptic vesicles as well as dense-core vesicles of granular appearance with diameters of either 500–1,000 Å or 2,000 Å. Isolated granulated fibers penetrate into the synaptic regions of the pineal organ. It is suggested that this extensive fiber system may be damaged during pinealectomy and that adjacent tissues containing fibers with granular inclusions may contaminate the pineal extracts. This may lead to false conclusions about the function of anuran epiphysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341994
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  • 5
    Electronic Resource
    Electronic Resource
    Fluoreszenzmikroskopischer Nachweis biogener Monoamine in der Epiphysis cerebri von Rana esculenta und Rana pipiens (1970)
    Springer
    Cell & tissue research 111 (1970), S. 550-558 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ (epiphysis cerebri) ; Anura ; 5-hydroxytryptamine ; Adrenergic nerve fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Epiphysis cerebri von Rana pipiens und Rana esculenta wurde fluoreszenzmikroskopisch auf das Vorhandensein bestimmter biogener Amine untersucht. Unter normalen Bedingungen lassen sich im Parenchym der Froschepiphyse keine Amine fluoreszenzmikroskopisch darstellen. Nach Vorbehandlung der Tiere mit dem Monoaminoxydase-Hemmer Nialamid ist aber eine intensive, durch Formaldehyd-Behandlung induzierte Gelbfluoreszenz in den Sinnes- und Stützzellen zu beobachten. Mikrospektrofluorometrische Messungen zeigen, daß das Fluorophor mit 5-Hydroxytryptamin identisch ist, obwohl das Vorkommen von anderen verwandten Indolen — z.B. 5-Hydroxytryptophan und Melatonin — nicht ausgeschlossen werden kann. Grünfluoreszierende adrenerge Nervenfasern sind im meningealen Hüllbindegewebe der Epiphyse zu erkennen; einige dieser Fasern scheinen auch in die Epiphyse einzudringen. Der Nachweis von 5-Hydroxytryptamin wird im Zusammenhang mit der Frage einer Melatoninsynthese diskutiert. Das 5-Hydroxytryptamin könnte außerdem in einer funktionellen Beziehung zu einem bisher noch unbekannten Protein- der Polypeptid-Hormon des Epiphysenparenchyms stehen.
    Notes: Summary The pineal organ of Rana pipiens and Rana esculenta was studied by fluorescence microscopy for the histochemical demonstration of certain biogenic monoamines. Under normal conditions, no fluorogenic amines were visible in the organ. After pretreatment of the animal with a monoamine-oxidase inhibitor, nialamide, an intense yellow formaldehyde-induced fluorescence appeared both in the sensory cells and in the supporting cells. Microspectrofluorometric analysis indicated that the fluorophore is identical with 5-hydroxytryptamine; the presence of other closely related indoles, such as 5-hydroxytryptophan and melatonin, however, cannot be excluded. Fluorescent adrenergic nerves were found in the connective tissues surrounding the pineal organ; fluorescent fibers were observed also in the pineal parenchyma. The presence of 5-hydroxytryptamine in the anuran pineal organ is discussed with regard to the role that the amine plays in melatonin synthesis and with regard to a possible functional relation to some as yet unidentified protein- or polypeptid-hormone within the pineal parenchyma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330931
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  • 6
    Electronic Resource
    Electronic Resource
    Strukturbesonderheiten der Anurenepiphyse nach prolongierter Osmierung und Anwendung der Acetylcholinesterase-Reaktion (1971)
    Springer
    Cell & tissue research 112 (1971), S. 526-541 
    Details
    ISSN: 1432-0878
    Keywords: Anura ; Pineal organ (epiphysis) ; Prolonged osmium tetroxide fixation ; Specific sensory cell and supportive cell structures ; Acetylcholinesterase reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Mit der prolongierten Osmierung nach Friend wird an den Außengliedern der pinealen Sinneszellen von Rana temporaria eine körnige Schwärzung erzielt. Diese Partikel haben einen Durchmesser von etwa 50 Å. In Analogie zu den Befunden an den retinalen Stäbchen (Eakin und Brandenburger) wird das geschwärzte Material als das Reaktionsprodukt eines Photopigments gedeutet. Weiterhin kann man mit dieser Methode in den pinealen Stützzellen 300–2500 Å große Granula darstellen, die im Golgi-Apparat entstehen. Die für Stützzellen charakteristischen Granula ermöglichen eine sichere Erkennung kleiner Stützzellanschnitte. Obwohl der Chemismus der Friendschen Reaktion nicht bekannt ist, bewährt sich diese Fixierungsmethode bei der elektiven Darstellung bestimmter Zellstrukturen. So war es möglich, den Degenerationsablauf an den Sinneszellaußengliedern und das Verhalten von Zellfortsätzen im perivaskulären Raum präziser als bisher zu untersuchen. Mit der Acetylcholinesterase-Reaktion können in der Anurenepiphyse nur Ganglienzellen und deren Neuriten elektiv hervorgehoben werden; basaler Rezeptorenfuß und die plexiformen Zonen sind dagegen negativ.
    Notes: Summary 50 Å particles are selectively demonstrated in the cytoplasmic lamellae of the outer segments of the pineal sensory cells inRana temporaria after prolonged osmium tetroxide fixation according to Friend. In analogy to the interpretations of Eakin and Brandenburger concerning the rods of the lateral eye, it is assumed that a photopigment is present in the outer segment of the anuran pineal receptors. Furthermore, 300–2500 Å granules are demonstrated in the supportive cells; these originate in the Golgi zone. The characteristic granules of supportive cells are an important feature in the demonstration of small supportive cell segments. The chemical basis of the Friend reaction is not completely understood. However, the reaction proves to be useful in the demonstration of certain cell organelles. A more precise picture of degenerating outer segments of pineal sensory cells and of the distribution of terminal processes of different pineal cell types in the perivascular spaces can be obtained by the prolonged osmium tetroxide fixation. The nerve cells of the anuran pineal organ and their axons are demonstrated selectively by the acetylcholinesterase technique. The basal feet-like processes of the receptor cells and the plexiform zones of the pineal organ are negative in acetylcholinesterase preparations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01033378
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  • 7
    Electronic Resource
    Electronic Resource
    Weitere experimentelle und neuroanatomische Untersuchungen an den Nervenbahnen des Pinealkomplexes der Anuren (1971)
    Springer
    Cell & tissue research 116 (1971), S. 250-274 
    Details
    ISSN: 1432-0878
    Keywords: Pineal complex ; Anura ; Nervus and tractus pinealis ; Chromatic and achromatic responses to light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Der Epiphysenkomplex von 32 Fröschen der Arten Rana temporaria, Rana esculenta und Rana catesbeiana wurde zuerst elektrophysiologisch, anschließend neuro-histologisch bzw. elektronenmikroskopisch untersucht. Auf Belichtung des Stirnorgans lassen sich vom Nervus pinealis (= Tractus frontalis) zwei Arten von Antworten ableiten. Antidrome elektrische Reizung des Tractus pinealis zeigt im Nervus pinealis fortgeleitete Aktionspotentiale und damit Nervenfasern, die vom Stirnorgan bis zum Mittelhirn durchgehen. Elektrophysiologisch wurden außerdem Fasern ermittelt, die die Epiphysis cerebri nicht erreichen. Weitere Fasern enden in der Epiphyse. Neben den vom Stirnorgan zum Gehirn ziehenden afferenten Fasern kann man im extracranialen Teil des Nervus pinealis auch efferente Fasern nachweisen. Histologisch ist in allen Fällen der Durchtritt des Nervus pinealis durch das Schädeldach zu beobachten. Der Durchmesser des Nerven nimmt jedoch wahrend seines Verlaufs kontinuierlich ab. Elektronenmikroskopisch konnte gesichert werden, daß diese Durchmesserabnahme auf einem Faserverlust beruht. Bei einer Rana catesbeiana wurden kurz vor Eintritt des Nervus pinealis in die Epiphyse — im Vergleich zum extracranialen Nervenabschnitt —nur noch die Hälfte der markhaltigen und 1/3 der marklosen Nervenfasern gezählt. Bei den verbleibenden markhaltigen Fasern war außerdem die Dicke der Markscheide stark reduziert. Der Nervus pinealis fächert sich in Epiphysennähe auf; seine Fasern treten dorsomedian einzeln durch die Basalmembran in das Parenchym des rostralen Epiphysenabschnittes ein. Gemeinsam mit den Neuriten der Epiphysennervenzellen bilden sie den Tractus pinealis (s. auch Paul u. Mitarb., 1971). Eine synaptische Umschaltung der Fasern des Nervus pinealis konnte in der Epiphyse nicht nachgewiesen werden. Bei einer Rana esculenta betrug der Faseranteil des Nervus pinealis am Tractus pinealis nur etwa 2%. Die Befunde werden im Zusammenhang mit der Entstehung und Leitung der chromatischen und achromatischen Antwort im Epiphysenkomplex diskutiert.
    Notes: Summary The pineal systems of 32 frogs of the species Rana temporaria, Rana esculenta, and Rana catesbeiana were studied first electrophysiologically and then with histological and electron microscopical methods. The nervus pinealis (= tractus frontalis) showed two kinds of responses to photic stimulation. Uninterrupted conduction of nerve impulses from the frontal organ to the midbrain was demonstrated by antidromic electrical stimulation of the intracranial pineal tract and recording of action potentials from the extracranial pineal nerve. Beside the uninterrupted fibres from the frontal organ to the tractus pinealis, other fibres of the nervus pinealis either did not reach the pineal organ or ended in the pineal organ. The extracranial part of the nervus pinealis contained afferent as well as efferent fibres. Morphologically it was shown in 32 investigated animals that the nervus pinealis penetrates the skull and runs to the pineal organ. During its course, the diameter of the pineal nerve became smaller, which was related to a decrease of the number of myelinated and unmyelinated fibres as revealed by the electron microscope. In comparison with the extracranial portion of the pineal nerve, the intracranial portion of the nerve near the pineal organ contained only half of the myelinated and one third of the unmyelinated fibres counted in one specimen of Rana catesbeiana. The thickness of the myelin sheats of the residual myelinated fibres was much reduced. The nervus pinealis entered the rostral region of the pineal organ, and single nerve fibres were seen to penetrate the basal lamina of the pineal organ reaching its parenchyma dorsomedially. These fibres, and axons of the nerve cells of the pineal organ, constituted the pineal tract (see also Paul et al., 1971). In one specimen of Rana esculenta, only ∼2% of the nerve fibres of the tractus pinealis originated in the frontal organ. The results have been discussed in relation to the generation and conduction of the chromatic and achromatic responses in the pineal system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331265
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  • 8
    Electronic Resource
    Electronic Resource
    Fluoreszenzmikroskopische und elektronenmikroskopische Untersuchungen am Pinealorgan verschiedener Vogelarten (1973)
    Springer
    Cell & tissue research 137 (1973), S. 37-62 
    Details
    ISSN: 1432-0878
    Keywords: Avian pineal organ ; 5-HT ; Adrenergic innervation ; Light-dependent functions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Mit der Fluoreszenzmethode von Falck-Hillarp lassen sich Artunterschiede im Innervationsmodus der Vogelepiphyse nachweisen. Bei Passer domesticus, Carduelis chloris, Pica pica, Corvus frugilegus und Gallus domesticus treten fluoreszierende adrenerge Nervenfasern nur perivaskulär, bei Anas platyrhynchos und Excalfactoria chinensis sowohl perivaskulär als auch im Parenchym, bei Columba livia lediglich vereinzelt im Parenchym auf. Die Fluoreszenzintensität des Epiphysenparenchyms von Passer domesticus und Columba livia, die nach mikrospektrographischen Messungen auf Serotonin beruht, schwankt stark von Fanggruppe zu Fanggruppe; die großen Unterschiede sind durch tagesrhythmische Schwankungen allein nicht erklärbar. In permanenter Dunkelheit nimmt die Serotoninfluoreszenz der Taubenepiphyse beträchtlich zu. Serotonin wird auch von den aminergen Nervenfasern der Vogelepiphyse gespeichert; seine Abgabe in die Blutbahn und deren physiologische Bedeutung werden diskutiert. Die in das Lumen der Vogelepiphyse hineinragenden, von modifizierten Zilien der Pinealozyten ausgehenden Membranwirbel zeigen mit der Osmierung nach Eakin, Brandenburger, Kopsch, Kolatschev gleichartige Partikel (Durchmesser 50 Å) wie die regulär gebauten Außenglieder der retinalen und pinealen Photorezeptoren. Diese Befunde werden mit elektrophysiologischen, biochemischen und verhaltensphysiologischen Ergebnissen verglichen.
    Notes: Summary The adrenergic innervation and the parenchymal 5-HT in the pineal organ of different avian species were investigated with the method of Falck-Hillarp. The fluorophores were identified microspectrographically. An entirely perivascular localization of adrenergic nerve fibres was observed in the pineal organs of Passer domesticus, Carduelis chloris, Pica pica, Corvus frugilegus and Gallus domesticus. The pineal organs of Anas platyrhynchos and Excalfactoria chinensis showed both perivascular and parenchymal innervation. Perivascular fibres were absent from the pineal organ of Columba livia, and only a few fine fluorescent fibres appeared in its parenchyma after pretreatment with l-dopa. The intensity of the 5-HT fluorescence of the parenchyma cells showed a high individual variability. These differences apparently do not reflect a circadian 5-HT-rhythm. Continuous darkness increased the intensity of the 5-HT-fluorescence in the pineal organ of Columba livia. 5-HT was also demonstrated within the perivascular autonomic nerve fibres of the avian pineal organ. It is probable that 5-HT is released from the pineal parenchyma into the circulation. After prolonged osmium tetroxide treatment according to Eakin, Brandenburger, Kopsch, Kolatschev, the membrane whorls that are formed by the cilia of avian pinealocytes showed osmiophilic particles 50 Å in diameter. Similar particles have been observed in the regular outer segments of retinal and pineal photoreceptor cells of lower vertebrates. The above morphological results are discussed in view of electrophysiological, biochemical and behavioural observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307048
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  • 9
    Electronic Resource
    Electronic Resource
    Weitere Untersuchungen zur Feinstruktur und Innervation des Pinealorgans von Passer domesticus L. (1970)
    Springer
    Cell & tissue research 105 (1970), S. 276-302 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ ; Passer domesticus ; Synapses ; Nervous pathway ; Sympathetic innervation ; Photo-neuro-endocrine organ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im Parenchym der Epiphysis cerebri von Passer domesticus kommen Nervenzellen vor. Ihre Neuriten ziehen im langgestreckten Epiphysenstiel zur Commissura habenularum. Im proximalen Endabschnitt des Epiphysenstiels wird ein Teil dieser Fasern myelinisiert. Zwischen die Nervenfasern schieben sich zahlreiche Pinealocytenausläufer; synaptische Bänder helfen die letzteren eindeutig zu identifizieren. Im Bereich der synaptischen Bänder liegen: 1. 300 Å Vesikel, 2. 300 Å Vesikel und 800–1200 Å Granula, 3. nur 800–1200 Å große granulierte Vesikel. Die Tatsache, daß in Pinealocytenausläufern nebeneinander synaptische Bänder und Granula vorkommen, und daß apikal in zilientragenden Zellen ebenfalls Granula nachweisbar sind, spricht dafür, daß bei Passer domesticus ein Pinealzelltyp sensorische und sekretorische Strukturmerkmale besitzen kann. Außerdem werden Kontaktsynapsen beobachtet; ihre praesynaptischen Fasern enthalten die gleichen Strukturelemente wie die Fasern mit synaptischen Bändern. Die Zahl der Mikrofibrillen und Mikrotubuli variiert in den Pinealocytenausläufern, in den postsynaptischen Dendriten und in den Neuriten so stark, daß es mitunter schwierig ist, diese Fortsatztypen einwandfrei zu unterscheiden und die Zahl der zum Gehirn ziehenden Neuriten exakt zu ermitteln. Efferente sympathische Nervenfasern dringen in die Bindegewebssepten der Epiphyse ein. Sie enthalten Granula mit einem Durchmesser von 300–500 Å und 800–1200 Å. Nach Injektion von Nialamid zeigen beide Granulatypen einen elektronendichten Kern. Mikrospektrographisch ist Serotonin und Noradrenalin in diesen Nervenfasern nachweisbar. Das Material dieser Studie enthält keinen fluoreszenzmikroskopischen oder elektronenmikroskopischen Hinweis darauf, daß die sympathischen Nervenfasern durch die Basalmembran in den Zellverband des Epiphysenparenchyms eintreten. Im elektronenmikroskopischen Bild haben manche Pinealocytenausläufer eine Ähnlichkeit mit autonomen Nervenfasern. Die funktionelle Bedeutung der Vogelepiphyse als photo-neuro-endokrines Organ wird diskutiert.
    Notes: Summary The pineal organ of Passer domesticus contains nerve cells within its parenchyma. Axons of the nerve cells run within the elongated stalk of the pineal organ to the habenular commissure. At the proximal end of the stalk, some axons become myelinated. In the stalk, the axons intermingle with pinealocyte processes containing synaptic ribbons. The synaptic ribbons are in contact with (1) vesicles with a diameter of 300 Å; (2) 300 Å diameter vesicles and 800–1,200 Å diameter dense-core granules; or (3) the dense-core granules only. Dense-core granules are also present in pinealocytes with 9+0 type cilia. These results suggest that sensory and secretory structures are present in the same pineal cell type. Furthermore, “conventional” synapses are present between receptor and nerve cells: The presynaptic fibers have the same structure as the fibers containing synaptic ribbons. The numbers of microfibrils and microtubules vary among postsynaptic fibers (dendrites), the pinealocyte processes, and the neurites. Thus it is difficult to obtain an exact count of the number of axons running to the brain. Efferent sympathetic nerve fibers enter the pineal organ associated with the connective tissue surrounding blood vessels. The fibers show granules of 300–500 Å diameter or 800–1,200 Å diameter. After nialamide injection, both types of granules contain a dense core. Microspectrographically serotonin and noradrenaline are demonstrated in the sympathetic nerve fibers. There is no evidence found in the material of this study to suggest that sympathetic nerve fibers perforate the basement membrane and enter the parenchymal cell complexes of the pineal organ. Pinealocyte processes and sympathetic nerve fibers often show a very similar ultrastructural pattern. The role of the avian pineal organ in photo-neuro-endocrine regulation is discussed.
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    URL: http://dx.doi.org/10.1007/BF00335477
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  • 10
    Electronic Resource
    Electronic Resource
    Cytochemical demonstration of acid phosphatase activity in the pineal organ of the rainbow trout, Salmo gairdneri (1986)
    Springer
    Cell & tissue research 245 (1986), S. 171-176 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ, Salmo gairdneri ; Cytochemistry ; Acid phosphatase activity ; Lysosomes ; Macrophages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Activity of acid phosphatase (ACP) was investigated cytochemically in the pineal organ of the rainbow trout, Salmo gairdneri. Intense reaction product for ACP activity was observed (1) in lysosomes varying in size and shape and (2) in endoplasmic reticulum associated with the Golgi complex of (i) the pineal photoreceptor and supporting cells, (ii) vascular endothelial cells, and (iii) macrophages inhabiting pineal lumen, parenchymal epithelium and perivascular spaces. This localization of ACP is discussed with particular reference to the capacity for lysosomal digestion in a pineal organ combining photoreceptive and secretory functions, and lacking a blood-brain barrier, as holds true for the pineal of the rainbow trout. Taking advantage of its capacity for endocytotic uptake and lysosomal digestion, the pineal organ of the rainbow trout may serve as a barrier between the blood circulation and the cerebrospinal-fluid compartment. Furthermore, the macrophages may be considered as an essential component in pineal function of fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218097
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