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  • Electronic Resource  (5)
  • 1995-1999  (1)
  • 1985-1989  (1)
  • 1980-1984  (3)
  • 1
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A disynaptic pathway linking the caudal ventrolateral medulla (VLM) to the spinal cord via the A5 noradrenergic cell group of the pons has recently been described in the rat. In the present work, the projections of the A5 to the VLM and to the spinal dorsal horn were studied with double-tracing techniques combined with immunostaining of the noradrenaline-synthesizing enzyme dopamine-β-hydroxylase. Cholera toxin subunit B (CTb) injected into the VLM and fluoro-gold injected into the spinal dorsal horn produced double retrograde labelling of A5 neurons immunoreactive for dopamine-β-hydroxylase, which received appositions of fibre varicosities labelled anterogradely with CTb injected into the VLM. After injecting CTb into the A5, retrogradely labelled neurons occurred in the VLM. These neurons were contacted by anterogradely labelled fibres from the A5 group. These observations indicate that the VLM cells acting upon the A5 spinally projecting neurons, which are likely to exert an α2-adrenoreceptor-mediated inhibition on the spinal cord, are targeted by collaterals of the A5 spinal cord-bound axons. The A5-VLM pathway may be the anatomical substrate of a negative feedback circuit whereby the modulatory action of the VLM on the spinal cord is self-inhibited through activation of the A5.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Neuronal population ; Lamina I ; Spinal cord ; Cell reconstructions ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Complete series of silver-stained semithin transverse sections were used to reconstruct 177 nerve cells of rat lamina I. According to the three-dimensional shape of the perikarya and the number and orientation of primary dendritic trunks, lamina I cells formed four distinct groups: (1) Fusiform cells with long rostrocaudal axis and having 1–4 primary dendrites oriented rostrocaudally or ventrally, which were the most numerous (50%) and predominated in the lateral third of lamina I. (2) Flattened cells (12%) which were thin discs of angular contour, spread out parallel to the lamina dorsal border; they emitted thick lateral and medial, but no dorsal or ventral, primary dendrites, and were mainly located in the middle third. (3) Multipolar cells (20%) with polyhedric somata emitting 4–12 primary dendritic trunks in several directions, which were practically confined to the medial third of the lamina. (4) Prismatic, wedge-shaped cells (18%), partly situated or encased, in the white matter, emitting one dorsal interstitial dendrite and several transversely oriented dendrites, which were distributed throughout the whole dorsal border of lamina I, though more abundant in its lateral portion. A subpopulation of large cells was identified in all groups, except in the multipolar one. These four cell types may help establish a basic morphologic classification of the neuronal population of lamina I, and may explain the different appearances under which local cells have previously been described in preparations using different planes of section and varied staining methods.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0568
    Keywords: Terminal degeneration ; Dorsal rhizotomy ; Glomeruli ; Spinal cord ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After cervical dorsal rhizotomy, small dark central terminals (CI) of glomeruli underwent electron dense changes at 8 h and were all degenerated at 36 h; their number persisted, though slightly diminished, up to 15 days, glial engulfment being negligible. Light large central terminals without neurofilaments (CIIa) showed electron-lucent or electron-dense degeneration from 14 to 36 h, while those with neurofilaments (CIIb) exhibited increased neurofilamentous areas, with depletion and presynaptic concentration of synaptic vesicles as in the electron-lucent change, at the 8–36 h postrhizotomy periods. Both CII-varieties were all degenerated at 36 h and became electron dense at 48 h; glial phagocytosis was intense and no terminals were present after 4 days. It is concluded that in the rat the 3 types of central glomerular terminals are primary axons, and that each type undergoes a different pattern of degeneration which points to a separate primary afferent origin. Numerous nonglomerular axodendritic endings began showing electron-dense degeneration at 8 h which rapidly masked their normal structure, although most appeared to contain round agranular vesicles, and some of them dense-cored vesicles (in lamina I). A few endings exhibited electronlucent degeneration. Labeling methods seem preferable for studying the primary origin of nonglomerular terminals, due to the difficulty in recognizing the normal predegenerative structure of these profiles.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 270 (1981), S. 325-331 
    ISSN: 1432-069X
    Keywords: Rat preputial gland ; Sebaceous glands ; Intracellular secretion ; Sexual hormones ; Hormonal control ; Preputiale Rattendrüsen ; Talgdrüsen ; interzelluläre Sekretion ; Sexualhormone ; hormonale Kontrolle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Durchmesser, der mit Sudanschwarz B gefärbten Talgtropfen und mit saurem Hämatin gefärbten perinukleären Granula und deren zahlenmäßige Dichte wurde in reifen preputialen Talgzellen normaler und mit Testosteron behandelter weiblicher Ratten sowie mit Östradial behandelter männlicher Ratten bestimmt. Mit Hilfe einer statistischen Analyse durch den Student-Test zeigte sich, daß der Durchmesser der Fetttröpfchen bei männlichen Tieren signifikant größer war als in den weiblichen Kontrollen, und daß Testosteron die weiblichen Werte zu der von normalen männlichen Kontrollen anhoben. Östradiolbehandlung verminderte die Werte unter den normaler weiblicher und männlicher Kontrollen und Testosteron-behandelter weiblicher Ratten. Der Durchmesser der perinukleären Granula veränderte sich innerhalb der verschiedenen Tiergruppen nicht, doch war die nunmehrige Dichtheit in den mit Testosteron behandelten Tieren größer als bei den normalen weiblichen oder mit Östradiol behandelten männlichen Ratten. Die Fetttröpfchen und die Fetttröpfchengröße sowie die Zahl der perinukleären Granula werden somit durch Androgene erhöht und durch Östrogene vermindert. Dies besagt, daß Sexualhormone nicht allein auf die Multiplikation der Talgdrüsenzellen oder auf die Umwandlungszeit, wie früher bereits berichtet, einwirken, sondern auch die Produktion der Lipide und die Freisetzung der β-Glucuronidase enthaltenden Granula in diesen Drüsen beeinflussen.
    Notes: Summary The diameters of Sudan Black B stained sebum vesicles and acid hematein stained perinuclear granules, and the numerical density of the latter, were determined in mature sebaceous preputial cells from normal male and female rats, testosterone-treated female rats and estradiol-treated male rats. Statistical analysis by Student's t-test showed that the diameter of lipid droplets was significantly higher in male than in female controls and that testosterone increased female values up to male control levels. Estradiol treatment decreased male values to levels below those of normal male and female controls and of testosterone-treated female rats. Diameters of perinuclear granules did not vary among animal groups but their numerical density was larger in testosterone treated than in normal female rats or estradiol treated male rats. Lipid droplet sizes and perinuclear granule numbers are thus increased by androgens and decreased by estrogens, which was interpreted as meaning that sexual hormones do not only act on sebaceous cell multiplication or turnover time as previously known, but also on the production of lipid and the output of beta-glucuronidase containing granules in this gland.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using serial section EM analysis, synaptic organization of glomeruli in lamina II of the dorsal horn of the rat has been examined. Four CI-terminals (small, dark and sinuous), four CIIa (large, light and regular, without neurofilaments) and four CIIb, (with neurofilaments) at the centres of synaptic glomeruli of types I, IIa and IIb, respectively, were serially sectioned and reconstructed. Asymmetrical synapses between the central terminal (C) and dendritic profiles without synaptic vesicles (D) prevailed in all types of glomeruli. Symmetrical dendroaxonic contacts with presynaptic dendrites (V1 → C) occurred practically only in type I glomeruli in which there were also more asymmetrical C → V1 contacts than in type II glomeruli. Symmetrical axoaxonic synapses V2 → C were more abundant in type IIa and IIb glomeruli. Type IIa glomeruli had a significantly larger number of C → D synapses and of all synapses per unit area of C surface, than type IIb glomeruli. Triadic systems with C and D postsynaptic to V2 were nearly as numerous as those involving V1 in type I glomeruli. Triads with V2 were however largely preponderant in type IIa and virtually exclusive in type IIb. It thus seems that each of the three types of glomerulus has its own pattern of synaptic interactions which might reflect specific complexes of feed-forward and feed-back mechanisms. In type I glomeruli, excitation of second-order neurons by nociceptive CI terminals may be controlled in similar proportions by presynaptic dendrites excited within the glomerulus by the C terminal itself, or by peripheral axons excited from outside the glomerulus. This kind of control is likely to prevail in type IIa glomeruli and to be the only efficient modulatory mechanism in type IIb glomeruli.
    Type of Medium: Electronic Resource
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