Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    STIM1 is a Ca 2+ sensor that activates CRAC channels and migrates from the Ca 2+ store to the plasma membrane (2005)
    [s.l.] : Nature Publishing Group
    Nature 437 (2005), S. 902-905 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] As the sole Ca2+ entry mechanism in a variety of non-excitable cells, store-operated calcium (SOC) influx is important in Ca2+ signalling and many other cellular processes. A calcium-release-activated calcium (CRAC) channel in T lymphocytes is the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature04147
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Transient decrease in F-actin may be necessary for translocation of proteins into dendritic spines (2005)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 22 (2005), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It remains poorly understood as to how newly synthesized proteins that are required to act at specific synapses are translocated into only selected subsets of potentiated dendritic spines. Here, we report that F-actin, a major component of the skeletal structure of dendritic spines, may contribute to the regulation of synaptic specificity of protein translocation. We found that the stabilization of F-actin blocked the translocation of GFP-CaMKII and inhibited the diffusion of 3-kDa dextran into spines (in 2–3 weeks cultures). Neuronal activation in hippocampal slices and cultured neurons led to an increase in the activation (decrease in the phosphorylation) of the actin depolymerization factor, cofilin, and a decrease in F-actin. Furthermore, the induction of long-term potentiation by tetanic stimulation induced local transient depolymerization of F-actin both in vivo and in hippocampal slices (8–10 weeks), and this local F-actin depolymerization was blocked by APV, a N-methyl-d-aspartate (NMDA) receptor antagonist. These results suggest that F-actin may play a role in synaptic specificity by allowing protein translocation into only potentiated spines, gated through its depolymerization, which is probably triggered by the activation of NMDA receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2005.04521.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The distribution of orthogonal arrays in the freeze-fractured rat median eminence (1982)
    Springer
    Journal of neurocytology 11 (1982), S. 335-349 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of orthogonal arrays of particles and their relationships to gap and tight junctions have been studied in the glia of the freeze-fractured rat median eminence (ME). These rectilinear clusters of intramembrane particles are thought to represent trans-membrane channels for ions or metabolites, and were found to be densely packed on the membranous laminations of the pial-glial limitans. Additionally, arrays were found to be present on all of the perivascular glial end-feet examined. Two classes of end-feet were distinguished by their relative densities of orthogonal arrays. End-feet displaying low densities of arrays occurred more frequently in the internal zone, while end-feet displaying high densities occurred more often in the external zone. Similar distinctions based on array density could be made in membranes from other regions of the cell as well. Cross-fractures revealing the cytoplasm underlying these membranes often exposed lipid inclusion bodies, suggesting that membranes containing few arrays belong to tanycytes (or to ‘astrocyte-like tanycytes’). The distribution of arrays appeared to be unrelated to the distribution of gap junctions in the membranes of astrocytes and tanycytes (and ‘astrocyte-like tanycytes’) of the ME, appearing near to and far from gap junctions with approximately equal frequency. Orthogonal arrays were absent from glial membranes near synaptic profiles in the ME. Arrays were also absent from the microvillous membranes of the apical surfaces of ependymal cells, from the cytoplasmic protrusions into the CSF of tanycytes, and from the vicinity of the tight and complex junctions linking the tanycyte and ependymal cell lateral membranes near their apical poles. These results suggest that there is a gradient of array density for most glia of the ME, increasing from the ventricular to the pial surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01258250
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Molecular specializations of the axon membrane at nodes of Ranvier are not dependent upon myelination (1979)
    Springer
    Journal of neurocytology 8 (1979), S. 719-735 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nodes of Ranvier from normal and ‘dystrophic’ mice have been examined with quantitative freeze-fracture electron microscopy. Regions of nodal, paranodal and interparanodal axolemma of normal fibres are clearly distinguishable on the basis of particle size distributions in electron micrographs of freeze-fractured replicas. Protoplasmic fracture faces of normal nodes of Ranvier, contain approximately 40% 100 Å particles and about 25% elongated particles 150 by 250 Å. Paranodal and interparanodal membranes contain a more uniform distribution of smaller diameter particles. ‘Dystrophic’ mice of the 129/ReJ-Dy strain have a genetic defect of Schwann cell development and myelinogenesis. Axons of the sciatic and deep peroneal nerves in dystrophic mice, which appear to be normally myelinated, possess approximately the same distributions of particles as axons in normal mice. However, in affected regions of the ventral and dorsal roots, Schwann cell wrappings may be missing, creating heminodes of Ranvier where the myelination terminates or begins again. At such heminodes, there is a circular band of axonal membrane which bears particles of sizes and packing densities similar to that found at normal nodes. High voltage electron microscopic examination of 0.25–1 μm thick sections from these hemi-nodal regions reveals the presence of a filamentous layer beneath the particle-rich membrane. In addition, completely amyelinated regions of root axons contain particle patches having size-density distributions similar to that of both normal and hemi-nodal membranes. Thus, the nodal membrane displays a characteristic particle-size distribution profile. The occurrence of this particle profile does not appear to be dependent upon the presence or absence of Schwann cells. These observations suggest that the functions subserved by the numerous particles at the node of Ranvier are not dependent upon myelination for their local differentiation within the axonal membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01206672
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Return of axonal and glial membrane specializations during remyelination after tellurium-induced demyelination (1982)
    Springer
    Journal of neurocytology 11 (1982), S. 65-80 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied remyelination of rat peripheral nerves after tellurium-induced demyelination using thin section and freeze-fracture techniques. In rats fed a 1% tellurium diet, regions of demyelination were readily identified by myelin debris and the presence of large denuded axons. Remyelination occurred despite continued tellurium ingestion. However, the demyelinated axons underwent a more rapid remyelination if tellurium was removed from the diet. Remyelination proceeded as described for myelination in the normal developing animal. Sites destined to become nodes of Ranvier were identified as patches of intramembranous particles in the axonal E-face. Early terminal loops of the remyelinating Schwann cell were found adjacent to these particle patches. As wrapping proceeded, terminal loops of myelin, along with associated rows of dimeric-particles characteristic of the axonal P-face, were wound into a paranodal location. This winding of the membrane specializations and associated terminal loops resulted in the reformation of morphologically normal paranodes. The size of the nodal E-face particle patch increased in concordance with increases in the number of paranodal loops until an annulus of particles was obtained as seen in the normal node. The thin section and freeze-fracture morphology of remyelinated fibres was indistinguishable from the morphology of control fibres. These observations are discussed with respect to proposed functions of membrane specializations in myelination and nerve conduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01258005
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The distribution of (Na+ + K+)ATPase is continuous along the axolemma of unensheathed axons from spinal roots of ‘dystrophic’ mice (1987)
    Springer
    Journal of neurocytology 16 (1987), S. 239-248 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary (Na++K+)ATPase-like immunoreactivity along the axolemma of sensory and motor neurons and the plasmalemma of Schwann cells from spinal roots of dystrophic mice (129 ReJ Dy/Dy) was determined using polyclonal antibodies specific for guinea pig renal (Na++K+)ATPase (GP-17), along with polyclonal (439-2) and monoclonal (9A5) antibodies specific for rat renal (Na++K+)ATPase. In normal and dystrophic mice, (Na++K+)ATPase-like immunoreactivity was observed along the axolemma at nodes of Ranvier using GP-17 and 439-2, each of which binds to isozymes of (Na++K+)ATPase composed of the α and α+ forms of the catalytic subunit. Staining was not seen along the nodal axolemma with 9A5, a preparation that binds to the α form of the catalytic subunit. The terminal processes and microvilli of Schwann cells were stained using all three antibody probes. The axolemma of unensheathed axons in dystrophic mice was continuously and uniformly labelled with GP-17 and 439-2, but not 9A5. Concentrations of (Na++K+)ATPase-like immunoreactivity along Schwann cell processes were observed most often in areas adjacent to unensheathed axolemma. At heminodes, staining abruptly decreased along Schwann cell processes in areas that were separated from the unensheathed axolemma by other intervening Schwann cell processes. It was concluded from these data that in dystrophic mice (Na++K+)ATPase is uniformly distributed along unensheathed portions of axons without evidence of detectable focal concentations of the enzyme, and that the catalytic subunit of (Na++K+)ATPase along unensheathed axons is distinct from the α form found in Schwann cells and other organs. In addition, (Na++K+)ATPase is concentrated along the plasmalemma of Schwann cells in regions of close apposition to axolemmal areas associated with large ionic fluxes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01795307
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The localization of sodium and calcium to Schwann cell paranodal loops at nodes of Ranvier and of calcium to compact myelin (1980)
    Springer
    Journal of neurocytology 9 (1980), S. 185-205 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary High-voltage electron microscopy (HVEM) has been used to determine the distribution of cationic precipitates in myelinated axons resulting from the application of two cytochemical techniques: a direct osmium pyroantimonate treatment for precipitating Na+, Ca2+ and Mg2+; and a 5 mM Ca2+ inclusion procedure (Oschman & Wall) for imparting electron density to Ca2+ binding sites. Electron probe wavelength spectroscopy was then used on semi-thick tissue sections to identify the species of ions present in the following regions: Schwann cell paranodal loops, axoplasm at the node, compact myelin and extracellular matrix. With these combined procedures we were able to localize elevated concentrations of both Na+ and Ca2+ to cytoplasmic compartments of the Schwann cell paranodal loops, as well as to detect the presence of Ca2+ at elevated levels in compact myelin. The involvement of the Schwann cell paranodal loops in providing a source and/or sink for Na+ involved in impulse conduction is suggested by these results, and the significance of such a role is discussed. A role for Ca2+ in the formation and stabilization of myelin lamellae is also suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205157
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Enhanced visualization of peripheral nerve and sensory receptors in the scanning electron microscope using cryofracture and osmium-thiocarbohydrazide-osmium impregnation (1981)
    Springer
    Journal of neurocytology 10 (1981), S. 111-131 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two methods of specimen preparation for the scanning electron microscope (SEM) have been combined for the reliable exposure and examination of nervous system tissue. When the specimen is postfixed with OsO4 prior to aqueous cryofracturing, large internal surfaces of nervous tissue are exposed, with minimal distortion to the cytoarchitecture. All tissue surfaces and interstices are subsequently impregnated with a conductive, metallic layer of osmium using a modified osmium-thiocarbohydrazide-osmium technique (OTOTO). This OTOTO technique permits SEM examination without any additional vacuum evaporated or ion-sputtered metallic layers, and has been found to eliminate specimen charging reliably. Nervous tissue has been examined in the secondary electron mode of the SEM with unrestricted use of beam currents varying from 1.3 to 60 μA, at accelerating voltages ranging from 2.5 to 80 kV, and at both low (10 ×) and high (80 000 ×) magnifications. In addition, a differential deposition of osmium in the tissue after the OTOTO technique has been identified using both transmission electron microscopy and energy dispersive X-ray microanalysis. The enhanced mass-density of myelin resulting from the amplification of osmium's natural affinity for unsaturated lipids was best demonstrated by the backscatter electron mode of the SEM. This mode of imaging was found useful in the identification of myelin sheaths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01181748
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The axoplasmic reticulum within myelinated axons is not transported rapidly (1983)
    Springer
    Journal of neurocytology 12 (1983), S. 393-411 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The axoplasmic reticulum in myelinated axons is an extensive system of branched smooth membranous tubules which is found throughout the length of large axons. To investigate its motility and possible role in fast axonal transport, a focal chilling method was used to arrest transport at two sites separated by a 3 mm wide warm region along the saphenous nerve of mice. The experiments ran for 3–4 h since axoplasmic material travelling faster than 25 mm/day would clear from the central warm region. The nerve was subsequently fixed and processed by a technique that enhances the electron density of the axoplasmic reticulum. Thin and thick sections from several regions along the nerve were then systematically studied using conventional and high voltage electron microscopy. In these studies we found that: 1. the axoplasmic reticulum does not accumulate against the proximal sides of the cold blocks; 2. although often closely associated, there is no evidence of continuity between the axoplasmic reticulum and the discrete membranous compartments that do accumulate proximal to the chilled regions; 3. the axoplasmic reticulum remains in the central 3 mm wide warm region; 4. the axoplasmic reticulum does not accumulate against the distal sides of the cold blocks; 5. retrogradely moving elements that do accumulate distal to the cold blocks do not fuse with the axoplasmic reticulum and are not contained in it; and 6. both retrograde and anterograde vector types are often closely associated with elements of axoplasmic reticulum. These results were supported by quantitative morphometric analysis. We conclude that the axoplasmic reticulum represents a discrete membrane system, separate from either anterogradely or retrogradely moving rapid transport vectors, and that this interconnected cisternal system itself is not rapidly transported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01159382
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructural and morphometric analysis of long-term peripheral nerve regeneration through silicone tubes (1988)
    Springer
    Journal of neurocytology 17 (1988), S. 161-172 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopy were used to investigate long-term regeneration in peripheral nerves regenerating across a 10 mm gap through silicone tubes. Schwann cells and axons co-migrated behind an advancing front of fibroblasts, bridging the 10 mm gap between 28 and 35 days following nerve transection. Myelination of regenerated fibres started between 14 and 21 days after transection and occurred in a manner similar to that reported during development. Although these early events were successful in producing morphologically normal-appearing regenerated fibres, complete maturation of many of these fibres was never achieved. Axonal distortion by neurofilaments, axonal degeneration and secondary demyelination were seen at 56 days following nerve transection. These changes progressed in severity with time as more axons advanced through the distal stump towards their peripheral target. Since regeneration occurs in the absence of endoneurial tubes, and because constrictive forces act on the nerve during regeneration, we suggest that these extrinsic factors limit the successful advancement of axons through the distal stump to their target organ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01674203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...