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At least 37 records · Page 2Linked to original sources
PubMed1978

Circadian oscillations of nucleic acid and protein content in functionally different neuron-neuroglia units of rat central nervous system.

Scanning integrating visible cytospectrophotometry of gallocyanin-, amido black-, fast green- or ammoniacal silver-stained sections of various areas of the central nervous system of adult rats sacrificed at 4 h intervals has demonstrated the presence of circadian changes in RNA, total protein and total histone content as well as in arginine-rich to lysine-rich histone ratio in the neurons and in their perineuronal satellite neuroglia. The peak of the content per cell of the macromolecular components studied was in some cases elevated above their lowest level up to 1.7-fold. The zenith in the content of neuronal RNA coincided as a rule with the nadir in the content of glial RNA whereas no such opposition was observed with respect to the protein or histone content as well as to the arginine- to lysine-rich ratio in the neurons and in their glial satellite cells. The data obtained have confirmed earlier observations that under changed conditions of neuron functioning, the changes in the nervous system metabolism occur which are localized not only in the neurons but also in the neuroglia, the metabolic response in the glial cells being characterized, depending on peculiarities of the particular neuron activity, both by similarity and by some differences as compared with the neuronal metabolic response. A synchronizing effect of environmental and/or internal factors on the macromolecular metabolism within various cell populations of the central nervous system is discussed.

Animals↗
PubMed1984

Karyometric, cytophotometric, and histoenzymatic studies on neuroglia of young rats subjected to CCNU (Lomustine) action.

Studies on the effects of CCNU on neuroglia cells of the central nervous system in young individuals were conducted on 19 Wistar strain rats, each given 2 mg doses of 0.25 CCNU in 7th and 12th d of life. Karyometric and cytophotometric studies proved that CCNU administered to young rats induced changes in oligodendroglia and astroglia of the central nervous system. The changes included significant increase in nuclei contour and in the area of nuclei cross-section in oligodendro- and astroglia cells, elongation of oligodendroglia nuclei and an augmented DNA content in the 2 neuroglia types. The observed karyometric and cytophotometric changes were more evident in oligodendroglia nuclei than in astroglia nuclei.

Alkaline Phosphatase↗
PubMed1986

Histoenzymatic, karyometric, and DNA cytophotometric studies on rat neuroglia following administration of BCNU (carmustine).

BCNU is a nitrosourea derivative applied in anti-neoplastic therapy. As a result of conversion under in vivo-conditions, products of alkylating properties are formed which derrange DNA metabolism, and products of carbamylating activity which disturb protein metabolism. Studies on BCNU neurotoxicity were performed on 20 adult rats of Wistar strain which were given the compound intraperitoneally, in doses corresponding to those used for tumour treatment in humans. Material for estimating unfavorable effects of the drug on central nervous system involved brains, the sections of which were subjected to histoenzymatic reactions and stained according to FEULGEN for karyometric studies and DNA cytophotometry. Size and shape estimates for nuclei of the cells and their DNA content were obtained using Morphoquant automatic microscopic image analyzer (VEB Carl Zeiss, Jena) and compared to those of neuroglia of control animals, given no drug. Multiple intraperitoneal injections of BCNU induced distinct histoenzymatic, karyometric, and cytophotometric changes in oligodendroglia and astroglia. In oligodendroglia, lowered NsE and AcP activities and augmented TPPase activity were noted while in astroglia decreased activity of the former 2 enzymes was associated with an augmented ATPase activity. In karyometric studies, significant decrease in the size of astroglia and in DNA extinction was noted. No karyometric or cytophotometric alterations were noted in oligodendroglia nuclei. Results of the presented studies may indicate primary injury to vascular walls and secondary damage to neuroglia.

Acetylcholinesterase↗
PubMed1998

Neuroglia: possible role in thermogenesis and body temperature control.

The neuroglia, especially astrocytes, constitute a cell mass capable of adaptive heat production, since both the metabolic substrates and the biochemical machinery for energy production and its regulation seem to be available in these cells. Earlier physiological studies from this laboratory have provided circumstantial evidence that rodents such as rats and rabbits may indeed be capable of increasing their cerebral heat production during acute cold exposure. Recent relevant literature on the ability of neuroglia of the mammalian CNS to synthesize and release different transmitters and modulators and to communicate mutually with neuronal elements is discussed in support of the idea that different glial cell types could also contribute to the central regulation of body temperature in addition to the more established similar function of the neuronal pathways. The present hypothesis may have relevance to changes in glial cell mass and activity that occur in patients during the course of aging, or in gliosis with a consequent tendency for epilepsy caused by head trauma, with a consequent decrease or increase of intracranial metabolic rate, respectively. Also, the possibility for glial contribution to the thermoregulatory changes seen in psychoses is discussed.

Adaptation, Physiological↗
PubMed1978

Calcified congenital arachnoid cyst with heterotopic neuroglia in wall.

Two unique findings, advanced calcification and ectopic neuroglia, were encountered in the wall of a giant congenital arachnoid cyst occurring in a 40 year old woman. The cyst almost totally filled the supratentorial subdural space of the left hemicranial cavity, was not connected with the subarachnoid space, and thus developed intra-arachnoidally. Its congenitally derived nature was supported by the unique finding of heterotopic neuroglia in the wall. Congenital arachnoid cyst must be distinguished from various cystic lesions within the central nervous system, including the neuroepithelial cyst which can arise throughout the neuraxis. It is suggested that pathogenesis of the congenital arachnoid cyst is related to aberrant flow of the ventricular cerebrospinal fluid into the developing leptomeninx in the process of differentiation of the subarachnoid space. The tract or pouch may occur within the arachnoid mater, and the cyst is formed intra-arachnoidally when the former filled with fluid is closed off from the subarachnoid space.

Adult↗
PubMedDate not supplied

Cerebellopontine angle arachnoid cyst harbouring ectopic neuroglia.

Arachnoid cysts are collections of cerebrospinal fluid covered by arachnoidal cells and collagen. They may have a congenital or acquired origin. We present the case of a 7-year-old boy with a cerebellopontine angle arachnoid cyst harbouring a portion of neuroglia. Microscopically, the cyst wall consisted of a delicate fibrovascular membrane lined by a layer of arachnoidal cells. A thin layer of glial tissue ran the whole length of the cyst wall. This finding supports a congenital origin for this case. Cerebellopontine angle arachnoid cysts harbouring neuroglia without ependymal elements are very rare lesions and may be successfully treated by surgical resection.

Arachnoid Cysts↗
PubMed1976

[RNA concentration in neuron-neuroglia systems of the retina and visual zones of the cerebral cortex during light deprivation and light stimulation].

A two-wave-length cytophotometry of the gallocyanin-chromium alum-stained preparations showed that in adult rats kept for 30 days in complete darkness there was a decrease in the RNA content in the perineuronal neuroglia of the retinal ganglion cell layer only, with no changes in the corresponding neurons. No changes were found in the neurons and in the perineuronal glia of the layer II---III of the visual cerebral cortex. After the end of light deprivation a 2-hour stimulation with a constant or flickering light did not influence the RNA content in the neurons of both regions of the visual analyzer studied, whereas in control rats this stimulation induced a marked increase in the RNA content in these neurons. Qualitative changes in the metabolism of the cellular RNA in the nervous system of adult animals under the effect of light deprivation are emphasized. Differences in the biochemical peculiarities of various neuron-neuroglia systems, depending on their localization in the visual analyzer, are discussed.

Animals↗
PubMedDate not supplied

[ATPase activity in neurons and neuroglia during convulsions induced by picrotoxin].

Na+,K(+)-ATPase activity was studied in neurones and neuroglia under conditions of convulsions caused by picrotoxin administration. Picrotoxin is a stimulant which causes convulsions by suppression of presynaptic inhibition. Na+,K(+)-ATPase activity in neuroglia was increased in convulsion, bat was not altered in neurones. It is possible, that glial Na+, K(+)-ATPase activity plays the role of neuronal ion's flows regulator and neuronal protector from convulsions. In recovery period ATPase activities in neuronal and neuroglial cells run up to control.

Animals↗
PubMed1988

[Neuroglia-form cells in the visual cortex of the rat].

Neuroglia-form cells have been examined in visual cortex of the rat in Golgi-Kopsch-preparations. These small neurons with strictly local and dense dendritic and axonal plexuses are present in all cortical layers. Neuroglia-form cells of the rat are identical with the same neuronal types described by previous authors in cortical areas of other species, guinea pig, cat, monkey and in man.

Animals↗
PubMed1987

Immunological probes reveal spatial and developmental diversity in insect neuroglia.

A set of monoclonal antibodies (MAbs) has been generated that recognizes distinct classes of neuroglia in the adult nervous system of the cricket Acheta domesticus corresponding to glial types distinguished by morphological criteria. These include antibodies that bind to the neuroglia of the ganglionic cortex, perineurium, neuropil, and glia associated with the glial lacunar system (interface) and fiber tracts. Another MAb specifically labels components of the neural lamella, a complex extracellular matrix secreted by underlying perineurial cells. Selected adult glial-specific MAbs recognize particular glial antigens expressed during embryonic development of Acheta. Immunohistochemical staining of frozen sections of late- (90-95%) and intermediate- (50-55%) stage whole embryos reveals that the spatial distribution, degree of tissue restriction, or level of expression of some glial determinants changes as development proceeds. Labeling of certain neuroblasts in the embryonic CNS at 50-55% development by an antibody (MAb 3G6) that binds to neuropil glia in the adult CNS implies that at least 1 class of insect glia may be generated by these cells.

Animals↗
PubMed1978

[Protein concentration in the neuron--neuroglia system of the anterior horns of the spinal cord in rats following exposure to the tranquilizer diazepam against a background of anticipation stress].

Anticipation stress was induced in 16 day-old male rats by placing the animals daily for 7 days into individual cells for 45 min. In the end of each 45 min session, an electric stimulation of paws of the animals was done for 2 min. It was shown by visible cytospectrophotometry of amido black-stained spinal cord sections that the anticipation stress for 7 days resulted in an accumulation of the nuclear and cytoplasmic total proteins in the motoneurons of spinal cord anterior horns, with no changes in the body (in fact, in the nuclei) of the glial cells adjacent to the neurons. Intraperitoneal injection of the tranquilizer diazepam (10 mg per kg) 40 min. before the beginning of the last anticipation stress session gave rise to the return to the normal of the protein content per cell in the motoneuron nucleus and cytoplasm while inducing an increase in the quantity of neuroglia cell protein. Differences in the protein metabolism between the neurons and the neuroglia are discussed.

Animals↗
PubMedDate not supplied

[Metabolism of different phospholipid fractions in neurons and neuroglia during myelinization].

Fractions, enriched with neurones and neuroglia, were isolated from brain cortex of 10, 20 and 30 days old rats using preparative ultracentrifugation in sucrose and Ficoil density gradient. Metabolism of phospholipids in neurones and neuroglia during the period of intensive myelinization was shown to have a number of specific properties resulting from the functional diversity of the cell populations in the central nervous system.

Aging↗
PubMed1981

Neuroglia in amphibian (Rana tigrina) central nervous system.

Neuroglia in the vertebrates are primarily classified as (i) Ependymal and (2) Non-ependymal gliocytes. In the present study neuroglia in the brain and spinal cord of Frog (Rana tigrina) has been studied under the light microscope using rapid Golgi, Holzer, and Luxol fast blue-neutral red staining methods. Ependymal glial cells with long processes having vascular and/or superficial terminal contacts, non-ependymal primitive glial cells (unipolar and bipolar) and phylogenetically more mature non-ependymal glial cells conforming to the classical description of astrocytes, oligodendrocytes and microgliocytes have been observed. It is interesting to note that oligodendrocytes of classical morphology have been observed in close relation to non-myelinated nerve fibres suggesting that nerve fibre-oligodendrocytes relationship may also be other than myelinogenesis.

Animals↗
PubMedDate not supplied

[Effect of hyperoxia on RNA and protein concentration in cortical and spinal motor neurons and surrounding neuroglia].

Double-beam recording visible cytospectrophotometry showed that 30-minute convulsions due to 6 at. ga. hyperoxia result in a decrease in the RNA and protein content per cell in layer V neurons of the cerebral motor cortex and in the motoneurons of spinal cord anterior horn in albino rats. A decrease is also found in the glial cells, except for a spinal cord neuroglia. A decrease in the RNA content in the neurons as well as the protein content in the neurons and glia of the spinal cord is more pronounced than in similar structures of the cerebral motor cortex. The quantity of RNA and protein in the neurons and neuroglia of the cerebral cortex remins decreased for 24 h after hyperoxia cessation. In the spinal cord motoneurons the level of the RNA and protein becomes normal 3 h after hyperoxia, and 24 h later it exceeds the initial one.

Animals↗
PubMed1976

[Scanning intergrating cytospectophotometry of tightly apposed micro-objects (as an example, a study of the circadian rhythm of RNA and protein concentrations in different neuron--neuroglia systems)].

A scheme of electron aperture is described which permits a scanning intergrating cytospectrophotometry of adjacent microobjects. Results are presented of such cytophotometry to determine RNA and protein content in various neuron--neuroglia units of the rats studied every 4 hours during 24 hours period. Contraphase character of circadian fluctuations has been shown for RNA level in cerebllum Purkinje cells, hypothalamus supraoptic neurons and spinal cord motoneurons as compared with the fluctuations in corresponding glial satellite cells. Protein content fluctuations were of contraphase character only in the spinal motoneurons and in their perineuronal glia, whereas in all the other neuron-neuroglia units the period of fluctuations was rather similar in the neurons and in the glial cells. A great value of quantitative cytochemical methods is outlined to carry out a functional biochemical analysis of nervous tissue cells.

Animals↗
PubMed1996

Morphology of neuroglia in the antennal lobes and mushroom bodies of the brain of the honeybee.

We investigated the distribution and anatomical organization of glial cells in the antennal lobes and mushroom bodies of the honeybee. Reconstructions from serial sections, prepared according to the ethyl gallate method, revealed the entire morphology of glial cells in neuropiles, tracts, and the soma rind. The distribution of the glial cell bodies in the neuropiles was derived from the staining of cell nuclei with a fluorescent dye. There are glial cells of different shape in the soma rind which are wrapped around the neuronal cell bodies of the antennal lobes and the Kenyon cells of the mushroom bodies. Glial cells surround neuropilar areas such as the external and lateral sides of the glomeruli of the antennal lobes. Whereas we could not detect glia in the glomerular neuropile, glial cells with long processes are located in the core of the antennal lobe. Extensions of these glial cells also invade tracts containing the olfactory projection neurons. A layer of glial cells separates the mushroom body neuropile from the surrounding protocerebral neuropile. The neuropile of the mushroom bodies is clearly compartmented by glial cells. There is a high density of astrocyte-like glia in a column of the pedunculus which can be followed to the ventral part of the alpha-lobe. A network of mushroom body intrinsic glial cells separates the alpha-lobe from the beta-lobe and the pedunculus. This anatomical description of glial cell types in olfactory information processing pathways of an insect brain provides a framework for further physiological studies of neuroglia in dissociated cell culture.

Animals↗
PubMed1993

The differentiation between neuroglia and connective tissue sheath in insect ganglia revisited: the neural lamella and perineurial sheath cells are absent in a mesodermless mutant of Drosophila.

Two morphogenetic mutations, twist and Delta, that affect the embryonic development of Drosophila in known ways were used to examine the derivation and function of the outer layers of the central nervous system (CNS). Both the extracellular neural lamella, which ensheaths the CNS, and its source, the underlying perineurial sheath cell layer, fail to develop in Drosophila embryos that are homozygous for a loss of function mutation in the twist gene, and which thus lack mesodermal derivatives. The cell layer immediately below the perineurial sheath cells, here termed barrier glial cells, constitute the ion permeability barrier in wild-type embryos. They are present in twist mutant embryos, appear to be normal at the ultrastructural level, and function as a blood-brain ion barrier. The apparent derivation of perineurial sheath cells from mesodermal precursors distinguishes them from neurons, glia and other nonneural components of the CNS, such as tracheae, all of which are of ectodermal origin. We confirm Scharrer's interpretation of the relationship between the perineurium and underlying neuroglia. In embryos homozygous for the neurogenic mutant Delta, an embryonic lethal in which excess ventral blastoderm gives rise to neuroblasts, the CNS forms as an amorphous cell mass, with discontinuous perineurial sheath and barrier glial cell layers. We propose that the cell mass is permeable to lanthanum ions and fails to form a blood-brain barrier because volume growth prevents the formation of continuous surface cell layers.

Animals↗
PubMed1988

Nervenkitt: notes on the history of the concept of neuroglia.

The evolution of concepts concerning the identity and the functions of neuroglia is traced. Some of the main ideas in the works of Virchow, Deiters, Golgi, Lenhossék, Lugaro, Ramón y Cajal, del Río-Hortega, Achúcarro, Penfield, and others are highlighted.

Animals↗