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F Hajós

Publications and source records attributed to F Hajós.

At least 73 records · Page 4Linked to original sources
PubMed1984

Differential localization of GABA-dependent and GABA-independent benzodiazepine binding sites within synapses of rat cerebral cortex.

Fractions containing non-junctional membranes (fraction 1) could be separated from those enriched in junctional complexes (fraction 2) by sucrose gradient centrifugation of osmotically disrupted rat cerebral cortex synaptosomes. [3H]flunitrazepam binding sites were found to be homogeneous characterized by Kd = 0.65 nM, Bmax = 13 pM for fraction 1; and Kd = 2 nM, Bmax = 45 pM for fraction 2. GABA-dependent benzodiazepine receptor sites were found to be localized to the junctional complex fraction, while non-junctional membranes showed GABA-independent receptor and acceptor binding sites.

Animals↗
PubMed1984

Mosaicism of the ventricular layer as the developmental basis of neocortical columnar organization. A 3H-thymidine autoradiographic study in newborn mice.

The ratio and local distribution of intensely and weakly labelled neurons as compared with unlabelled neurons were studied in newborn mice by means of autoradiography using 3H-thymidine injected at various embryonic ages. The distribution and migrational properties of intensely labelled neurons suggest that cells contributing to any given cortical layer are not generated simultaneously but in smaller units that correspond to cortical microcolumns. This implies a mosaicity in the genetic potential of the ventricular germinative layer.

Animals↗
PubMed1984

Localization of alpha-tubulin immunoreactivity to cerebellar Bergmann glia with the TU 01 antibody.

The TU 01 antitubulin antibody specific for alpha-tubulin was demonstrated, by light- and electron-microscopic immunocytochemistry, to stain selectively the Bergmann glia of rat cerebellum. Within the glial cells and their fibres the microtubules, the smooth endoplasmic reticulum, the outer mitochondrial membranes and the ribosomal rosettes of the cell body were decorated by the antibody. The high selectivity of this antibody is discussed in terms of tubulin microheterogeneity.

Animals↗
PubMed1983

Two pools of electron cytochemically demonstrable adenylate cyclase activity in cortical synaptosomes.

Adenylate cyclase activity was demonstrated by means of electron microscopic cytochemistry in rat cortical synaptosomes incubated under various conditions. It was found that only the reaction at the postsynaptic density could be enhanced by noradrenaline and postmortem storage, while that on the presynaptic limiting membrane was insensitive to these effects but was affected selectively by vinblastine. On these grounds two different pools of cytochemically demonstrable adenylate cyclase activity were distinguished within the synaptic region.

Adenylyl Cyclases↗
PubMed1982

Transport of horseradish peroxidase by processes of radial glia from the pial surface into the mouse brain.

The transport of horseradish peroxidase (HRP) applied to exposed pial surfaces of the brain was studied in newborn, 4-, 7- and 12-day-old, and adult mice. In the telencephalon the cell bodies of radial glia were found to accumulate the tracer. Labeled cells occurred in the subventricular zone of the lateral ventricle during the first postnatal week; they became gradually restricted to an area around the stria terminalis (ventrolateral ventricular corner) by day 12. At later stages no HRP transport could be traced from the surface of the telencephalon. In the cerebellum, HRP was transported from the surface to the cell bodies of Bergmann glia in all age groups studied including adult animals. It is concluded that radial glia and their derivatives share the capacity of transporting material between various cerebrospinal fluid compartments.

Animals↗
PubMed1982

Comparative studies of fresh and postmortem isolated rat cortical synaptosomes: morphology, K+ transport, and respiration.

Synaptosomal fractions were isolated from rat cerebral cortex immediately and at 1, 2, 3, and 4 h postmortem. The capability to undergo function-dependent configurational changes in relation to ouabain- and protoveratrine-sensitive K+ uptake, and the rate of O2 consumption were compared between fresh and postmortem synaptosomal fractions. Our results suggest that a 2 h postmortem storage at room temperature does not decrease substantially the functional performance of synaptosomes, while longer storage periods interfere with their capacity to maintain intracellular cation levels. The findings appear to be relevant to the use of human autopsy material for the preparation of synaptosomes.

Biological Transport↗
PubMed1982

The separation of a fraction enriched in purely inhibitory nerve terminals from rat cerebellum.

The separation of a fraction enriched in cerebellar Golgi axon terminals of well-established inhibitory nature is described. The procedure is based on the phenomenon that the incubation of cerebellar glomerulus particles (isolated by a method described earlier) in saline media leads to the selective destruction of mossy terminals and of dendrites synapsing with them, whereas Golgi axon terminals remain intact. A 60-70% enrichment in Golgi terminals was achieved as revealed by electron microscopy.

Animals↗
PubMed1981

Immunocytochemical demonstration of glial fibrillary acidic protein in mouse tanycytes.

Immunohistochemical techniques were used to stain for the astrocytespecific glial fibrillary acidic protein (GFAP) in the cells lining the third ventricle of the developing and mature mouse brain. Before birth immunoreactive tanycytes were only observed in the infundibular recess of the median eminence, where they could first be seen at embryonic day 17. They possessed long processes running towards the ventral surface on the brain. During the early postnatal period GFAP-positive tanycytes gradually appeared throughout the third ventricle, although the ependymal cells themselves remained unstained. The tanycytes retained thier immunoreactivity for anti-GFAP serum in the adult, and were also evident in the adult rat third ventricle indicates that they, the transient radial glia of the developing cerebral cortex, the persistent Bergmann glia of the cerebellum, similar astrocytes with radial processes in the hippocampal dentate gyrus and conventional astroglia are all closely related cell types.

Animals↗
PubMed1981

Radial glia in the developing mouse cerebral cortex and hippocampus.

The regional distribution of radial glia in the developing cerebral cortex and the hippocampus of the mouse was studied using silver impregnation and immunocytochemical staining for glial fibrillary acidic protein (GFAP). Whilst the former technique revealed radial fibres at a slightly earlier age, immunocytochemistry gave a better picture of their general distribution and enabled systematic study of the appearance and disappearance of GFAP-positive radial glia throughout the cortex. Although a clear association between migrating neurones and radial glia was evident in the later stages of cortical plate formation, this relationship was not apparent in all cortical regions nor at the very early stages of the formation of the cortical plate. Even after allowing for a delayed appearance of GFAP immunoreactivity in relatively mature radial glia, the uneven distribution of these cells, their appearance after the cortical plate has already been formed, and their regional development in a pattern dissynchronous with that of the cortical plate argue against a general role of these structures in neuronal migration in the mouse, although there are notable phylogenetic differences.

Animals↗
PubMed1981

Electron microscopic demonstration of adenylate cyclase activity in rat cortical synaptosomes.

The electron cytochemical demonstration of adenylate cyclase activity was carried out in rat cortical synaptosomes. Reaction product was found in 60-70% of the synaptosomes in three predominant localization: (i) on the postsynaptic density; (ii) on the outer aspect of the synaptosomal membrane; (iii) inside the synaptosome. Results suggest that in addition to postsynaptic localization adenylate cyclase activity is cytochemically demonstrable also at presynaptic sites.

Adenylyl Cyclases↗
PubMed1981

The types of proliferating glioblasts in the immature mouse neocortex and dentate gyrus as revealed by electron microscopic autoradiography.

Proliferating glial elements of 3 to 12-day-old mouse parietal cortex and dentate gyrus were investigated by the electron microscopic autoradiography of 3H-thymidine. The presence in these regions of three types of proliferating glial precursors was verified and related to astrocyte development. Comparing the two areas studied it was concluded that postnatal glial proliferation is independent from neurogenesis and that astroglia is capable of proliferation even in advanced stages of differentiation.

Animals↗
PubMed1980

The structure of cleft material in spine synapses of rat cerebral and cerebellar cortices.

Synaptic clefts of rat cerebral and cerebellar axodendritic spine synapses were studied after aldehyde-perfusion and subsequent immersion into osmic acid or after processing by the aldehyde-PTA technique. The three-dimensional examination of aldehyde-perfused, osmic acid postfixed synapses revealed a double-layered intracleft lamina comparable in dimensions and position to the cleft density of non-osmicated, PTA-stained synapses. The relationship of this lamina to perisynaptic astroglial processes was pointed out. Densitometric analysis of the cleft area suggested the identity of the intracleft lamina of osmicated synapses with the cleft density of non-osmicated, PTA-stained synapses.

Animals↗
PubMed1979

The morphology of microtubules in incubated synaptosomes. Effect of low temperature and vinblastine.

A time-dependent rise in the percentage of microtubule-containing synaptosomes was observed reaching a 41--47% peak after 30 min incubation at room temperature (22--25 degrees C) in a saline medium. Fixation at low temperature or incubation with vinblastine decreased markedly the number of synpatosomes containing microtubules. It was concluded that incubation with cations and processing at room temperature were prerequisites of optimal preservation of synaptosomal microtubules. Their spatial orientation relative to the synaptic cleft was deduced from statistical examination of profiles in different orientations.

Animals↗
PubMed1979

Identification of early glial elements as the precursors of Bergmann-glia: a Golgi-analysis of the developing rat cerebellar cortex.

The developing rat cerebellar cortex was studied by the rapid Golgi procedure in 200 mu thick slices and in 1--2 mu thick semithin sections poststained with toluidine-blue. Glial cells having radial fibres directed towards the pial surface were found to be present continuously in the internal granular layer during cerebellar maturation. This cell type was identified as the developing Bergmann-glia.

Animals↗
PubMed1979

The effect of ethanol on the distribution of synaptic vesicles in cortical synaptosomes of the rat.

Ethanol was shown to cause a redistribution of synaptic vesicles in incubated synaptosomes. While the number of synaptosomes containing synaptic vesicles attached to the presynaptic membrane decreased markedly, an increase in the number of synaptosomes lacking membrane-vesicle associations was observed. The findings support the possibility of a presynaptic action of ethanol and point to the role of membrane-attached vesicles in synaptic transmission.

Animals↗