Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The protooncogene c-jun is highly expressed for long periods in axotomized PNS neurons. This may be related to their growth and regeneration. In contrast, axotomized CNS neurons show only a small and transient upregulation of c-jun. It has been suggested that there may be a correlation between this failure to maintain high levels of c-jun expression after axotomy and abortive CNS axonal regeneration. We have studied, by in situ hybridization and immunohistochemistry, the c-jun response after stab wound lesion, and after peripheral nerve grafting in the thalamus and cerebellum of the adult rat. A lesion elicits upregulation of c-jun in thalamic neurons ipsilateral to the lesion. This is most evident and prolonged in neurons such as those of the thalamic reticular nucleus, which have an established propensity to regenerate. After peripheral nerve grafting, the c-jun response in thalamic neurons is enhanced, mostly in neurons which have axons regenerating along the grafts. These neurons also upregulate growth-associated protein 43 (GAP-43). By comparison, injured Purkinje cells of the cerebellum which do not regenerate their axons along a graft, do not upregulate either c-jun or GAP-43, although they increase their expression of p75. Thus CNS neurons able to regenerate their axons along a peripheral nerve graft are those in which c-jun is induced after injury, and c-jun may play a critical role in the control of gene programs for axonal regeneration. Moreover, the observed differences in the ability of CNS neurons to regenerate their axons may relate to a difference in their intrinsic molecular response to axotomy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] New Zealand and Dutch Belted rabbits (not operated upon or surviving 3-143 days after unilateral optic nerve section or eye enucleation) were used. Most received an intraocular injection of colchicine, which is known to increase peptide levels in neuronal cell bodies4. Some received a unilateral ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 171 (1985), S. 223-234 
    ISSN: 1432-0568
    Schlagwort(e): Lateral geniculate nucleus ; Retinal axons ; Horseradish peroxidase ; Hamster ; Synaptic organization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The synaptic organization of the α sector of the dorsal lateral geniculate nucleus has been examined by electron microscopy in normal adult hamsters and in adult hamsters subjected to unilateral eye enucleation or intravitreal injection of horseradish peroxidase. Two types of neuropil are apparent. Islands of complex neuropil partially enclosed by astrocyte processes (synaptic glomeruli) are surrounded by a sea of simpler non-glomerular neuropil. The latter is dominated by small axon terminals with spherical synaptic vesicles and Gray type 1 axodendritic contacts (SR-boutons) and also contains axon terminals with flattened synaptic vesicles (F-boutons). The glomerular neuropil contains (i) exclusively postsynaptic dendrites and dendritic protrusions of presumptive projection cells; (ii) pre- and postsynaptic pleomorphic-vesiclecontaining P-boutons (interpreted as appendages of the dendrites of interneurons); (iii) large axon terminals containing spherical synaptic vesicles and large pale mitochondria (R-boutons) which were experimentally identified as retinal terminals and which are presynaptic to both projection cell dendrites and P-boutons at Gray type 1 contacts; (iv) F-boutons (minority component). F-boutons and P-boutons are presynaptic to both projection cell dendrites and P-boutons and P-boutons are the intermediate elements of various serial synapses including triplet (triadic) synapses. Medium-large terminals with spherical synatpic vesicles and dark mitochondria (RLD-boutons) which were commonly invaginated by dendritic spines of projection cells in small glomerulus-like formations were also identified. The origin of RLD-boutons is unknown but SR-boutons probably derive chiefly from ipsilateral visual cortex and possibly also from superior colliculus, and non-glomerular F-boutons probably originate in the ipsilateral thalamic reticular nucleus. No differences in synaptic organization were found between the part of the nucleus which receives uncrossed retinal input and the part which receives crossed input, nor were differences seen in the size, fine structure or relationships between the terminals of identified crossed and uncrossed retinal axons.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 1432-0568
    Schlagwort(e): Anterior thalamus ; Laterodorsal tegmental nucleus ; Pedunculopontine nucleus ; Cholinergic neurons Double-labelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Retrograde transport of horseradish peroxidase (HRP) was combined with choline acetyltransferase (ChAT) immunohistochemistry to study cholinergic projections to the anterior thalamic nuclei in the rat. Small iontophoretic injections of HRP placed into different subdivisions of the anterior thalamic nuclear complex resulted in distinct patterns of retrograde labelling in two major cholinergic cell groups of the mesopontine tegmentum, the laterodorsal tegmental nucleus (LDTg), in which a majority of the labelled cells was located, and the pedunculopontine tegmental nucleus (PPT). After injections into the posterior subdivision of the anteroventral thalamic nucleus (AVp), double-labelled neurons were present predominantly in the ipsilateral LDTg while a smaller number was found in the PPT. In the ipsilateral LDTg, 60–70% of ChAT-positive neurons were HRP-labelled, and 90–95% of the HRP-labelled neurons were ChAT-positive. In the contralateral LDTg, 30–40% of ChAT-positive neurons were HRP-labelled. After injections in the medial subdivision of the anteroventral thalamic nucleus (AVm), the pattern of labelling in LDTg was similar to that detected after injections in the AVp. The number of double-labelled neurons in the LDTg and PPT was much lower after injections into AVm than after injections into AVp. When injections were confined to the anterodorsal thalamic nucleus (AD), no HRP-labelled cells were present in the LDTg or PPT. These results show that the LDTg and PPT are the sources of the cholinergic input to the rat anterior thalamus. The major projection from LDTg and PPT is to the AVp, whereas there is a lighter cholinergic projection to the AVm. The AD does not receive a projection from cholinergic cells in the mesopontine tegmentum.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    ISSN: 1432-1106
    Schlagwort(e): Superior colliculus ; Horseradish peroxidase ; Connections ; Albinism ; Thalamus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Subcortical connections of the superior colliculus were investigated in albino and pigmented rats using retrograde and anterograde tracing with horseradish peroxidase (HRP), following unilateral injection of HRP into the superior colliculus. Afferents project bilaterally from the parabigeminal nuclei, the nucleus of the optic tract, the posterior pretectal region, the dorsal part of the lateral posterior-pulvinar complex and the ventral nucleus of the lateral lemniscus; and ipsilaterally from the substantia nigra pars reticulata, the pars lateralis of the ventral lateral geniculate nucleus, the intergeniculate leaflet, the zona incerta, the olivary pretectal nucleus, the nucleus of the posterior commissure, the lateral thalamus, Forel's field H2, and the ventromedial hypothalamus. Collicular efferents terminate ipsilaterally in the anterior, posterior and olivary pretectal nuclei, the nuclei of the optic tract and posterior commissure, the ventrolateral part of the dorsal lateral geniculate nucleus, the pars lateralis of the ventral lateral geniculate nucleus, the intergeniculate leaflet, and the zona incerta; and bilaterally in the parabigeminal nuclei and lateral posterior-pulvinar complex (chiefly its dorsal part). The general topographical patterns of some of the afferent and efferent projections were also determined: the caudal and rostral parts of the parabigeminal nucleus project to the caudal and rostral regions, respectively, of the superior colliculus; caudal superior colliculus projects to the most lateral, and lateral superior colliculus to the most caudal part of the terminal field in the dorsal lateral geniculate nucleus; caudolateral superior colliculus projects to the caudal ventrolateral part of the ventral lateral geniculate nucleus, while rostromedial parts of the colliculus project more rostrally and dorsomedially. Following comparable injections in pigmented and albino animals, fewer retrogradely labelled cells were found in subcortical structures in the albino than in the pigmented rats. The difference was most marked in nuclei contralateral to the injected colliculus. Thus, the effects of albinism on the nervous system may be more widespread than previously thought.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 73 (1988), S. 519-522 
    ISSN: 1432-1106
    Schlagwort(e): Retinogeniculate pathway ; Axonal branching ; Dorsal lateral geniculate nucleus ; Anterograde HRP labelling ; Visual system development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Between E15 and P4 in the hamster, axons of retinal ganglion cells in the optic tract over the dorsal lateral geniculate nucleus, are invaginated by, and make synaptic contacts with, small processes interpreted as tips or appendages of geniculate dendrites. In some cases a branch-like protrusion emerges from the axon at or close to the invagination. We hypothesize that the invaginations may be part of the mechanism by which retinocollicular axons are induced to branch and establish the retinogeniculate pathway.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    ISSN: 1432-1106
    Schlagwort(e): Key words Anterodorsal thalamic nucleus ; Anteroventral thalamic nucleus ; Retrograde labelling ; Postembedding immunoelectron microscopy ; Inhibitory synapses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  We have carried out a semi-quantitative ultrastructural study to determine the characteristics and distribution of γ-aminobutyric acid (GABA)-containing constituents of the anterodorsal (AD) and anteroventral (AV) thalamic nuclei in adult rats. We used a polyclonal antibody to GABA and a postembedding immunogold detection method in animals in which the cortical projection neurons of these nuclei had been labelled by retrograde transport of cholera toxin/horseradish peroxidase (HRP) injected into the retrosplenial granular cortex. Two types of GABA-immunopositive structures were identified, with gold particle densities 4–40 times higher than the highest densities over blood-vessel lumens and areas of empty resin: (1) an apparently homogeneous population of axon terminals with Gray type-2 (symmetric) synaptic contacts corresponding to F-axon terminals; and (2) small–medium sized myelinated axons scattered individually or in small groups within the neuropil which may be their parent axons. These axons and terminals may originate from the ipsilateral thalamic reticular nucleus; others may arise from the basal forebrain or brainstem. The GABA-immunopositive terminals comprised approximately 16% of all axon terminal profiles in AD and 12% in AV, a significant difference. However, because the immunoreactive axon terminals in AD were significantly larger than those in AV (1.09±0.47 µm2 vs 0.90±0.43 µm2) and would therefore be encountered more frequently, it is not possible to conclude that the GABAergic innervation of AD is heavier than that of AV. The GABA-positive terminals established synaptic contacts with cell bodies and dendrites of all sizes (some of which were HRP-labelled) with the following frequency distribution (AD/AV, no significant difference): somata 5%/7%; large dendrites (≥1.5 µm) 14%/9%; medium dendrites (1.00–1.49 µm) 35%/45% and small dendrites (〈1 µm) 46%/40%. Despite evidence from previous studies, we found no evidence in this study for the presence of GABAergic interneurons or for GABA-containing projection neurons in AD or AV.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    ISSN: 1432-1106
    Schlagwort(e): Key words Amino acid immunocytochemistry ; Axon collateralization ; Thalamus ; Fluorescent tracers ; Limbic system ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Small, stereotaxically guided injections of true blue (TB) were made into the retrosplenial granular cortex (RSg) and of diamidino yellow (DY) into the dorsal portion of the rostral pole of the thalamic reticular nucleus (TRN) in 16 adult rats to determine whether axons projecting from the anterior thalamic nuclear complex (ATN) to the TRN are branches of axons also projecting to the RSg. Following injections of the fluorescent dyes, serial coronal sections of the brain revealed single retrogradely labelled, and large numbers of double retrogradely labelled neuronal cell bodies in the ipsilateral anteroventral and anterodorsal nuclei and smaller numbers in the anteromedial nucleus of the ATN complex. In a se- cond series of six adult rats with similar double injections of TB and DY, two sections in three were immunoreacted, one with antiserum against glutamate and one with antiserum against aspartate, using indirect immunofluorescence with rhodamine to detect reactive cells. The great majority of both single and double retrogradely labelled cell bodies were also immunoreactive for aspartate or glutamate. In addition, a moderate to small number of non-immunolabelled neurons projecting to the TRN and/or to the RSg were also found in all three nuclei of the ATN complex. These results are compatible with the possibility that large numbers of neurons in the ATN send axonal branches to both the RSg and the TRN, and that many such neurons use glutamate and/or aspartate as transmitters. The findings also suggest that the projections from the ATN might be heterogeneous with respect to transmitter phenotype.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurocytology 17 (1988), S. 277-278 
    ISSN: 1573-7381
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurocytology 17 (1988), S. 871-875 
    ISSN: 1573-7381
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...