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At least 19 recordsLinked to original sources
PubMed1977

[Trace changes in the quantity of RNA in neurons and neuroglia of the hypothalamic nuclei of the brain following short-term intermittent exposure to cold].

Adult albino rats were kept for 2 minutes at --20 degrees C, then for 5 minutes at 25 degrees C, this intermittent cooling being repeated 15 times. One hour after the end of the cooling, the RNA quantity per cell was determined by means of visible cytospectrophotometry to find the increase in the cytoplasm of medial preoptic area neurons and in the nuclei of their glial satellite cells as well as in the nuclei of the perineuronal glial cells of mammillary bodies. Two days after the rats had stayed at the room temperature, these RNA changey bodies the RNA content decreased. 3 days later, the RNA content in the whole neuron--neuroglia unit of the preoptic area returned to normal, while in the neurons and neuroglia of mammillary bodies augmented markedly: this augmentation was found as late as 15 days after the cessation of the cooling. 30 days after the end of the cooling, the RNA quantity in the mammillary body neurons returned to normal, whiel in the neuroglia of this hypothalamic nucleus decreased even lower than the normal level. The authors discuss the problem of a so-called "vegetative memory" and of the involvement of hypothalamic neuron--neuroglia units in the metabolism tranformation dealing with a consolidation of this memory.

Adaptation, Physiological↗
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↗
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↗
PubMed1979

Differential radiosensitivity of neurons and neuroglia of the hippocampus in the adult rabbit.

Adult rabbits were subjected to 4.5 Gy of whole-blody or brain alone gamma-irradiation, and their hippocampus was examined with the light and electron microscope. Pycnotic cells were found at the base of the granular layer of the dentate gyrus in the so-called subgranular zone, as soon as 3 h after irradiation, and were cleared up by active phagocytosis after 48 h. Some of these cells appeared as undifferentiated, whereas others were differentiating granule cells, and possibly immature neuroglia. The extent of cell necrosis was contingent upon the age of the animal, the oldest animal studied (27 months) showing only sparse lesion of that type. Astrocytes and microglia were responsible for the phagocytosis of dead cells. Another type of lesion was found in the nuclei of the mature granule cells and consisted of light spots which appeared 1 h after the irradiation and disappeared almost completely after 48 h. Pyramidal cells did not show any of these two lesions. It is concluded that the laterations in the electrical activity of pyrimidal cells, following irradiation, are at least partly due to lesions affecting the dentate gyrus. Radionecrosis in the subgranular zone is related to the presence of immature cells in this region.

Age Factors↗
PubMed1979

Immunocytochemical localization of cyclic GMP: light and electron microscope evidence for involvement of neuroglia.

Guanosine 3',5'-cyclic monophosphate (cGMP) immunoreactivity in the rat's cerebellum was studied with light and electron microscopy by the indirect fluorescence method and the peroxidase-antiperoxidase method. Labeled cells included neuroglial cells in the cerebellar cortex, white matter, and deep nuclei; some stellate and basket cells in the cortex; and some large neurons in the deep nuclei. No evidence was found for sagittal microzonation in the cGMP distribution. In the labeled cells, cGMP immunoreactive sites were localized to surface membranes, organelles, and the cytoplasmic matrix. Specificity was indicated by the same pattern of labeling after treatment with cGMP immunoglobulin that had been adsorbed with adenosine 3',5'-cyclic monophosphate (cAMP) and by the failure to label after treatment with normal rabbit sera or with cGMP immunoglobulin that had been adsorbed with 1 mM cGMP. Cerebella treated with cAMP antisera, however, showed immunoreactivity in Purkinje cells, granule cells, and Golgi cells in addition to neuroglia in cortex and deep nuclei. Sequential norepinephrine and glutamate superfusions generally intensified cGMP immunoreactivity, not only in neuroglial cells but also in the background. Under these conditions some Purkinje cells and some granule cells were also labeled. Increased cGMP immunoreactivity was also obtained by treatment with harmaline, gamma-aminobutyric acid and aminooxyacetic acid, muscimol, gamma-aminobutyric acid, or apomorphine in order of decreasing effectiveness. Serotonin and colchicine produced no detectable increase of cGMP immunoreactivity above normal, and diazepam and sodium pentobarbital decreased it. In these experiments, diethyl ether was preferable to sodium pentobarbital for anesthesia on account of the depressive action of the latter on cGMP immunoreactivity. Thus, drugs that increase cerebellar activity enhance cGMP levels, whereas those that decrease cerebellar activity decrease cGMP levels. However, it is not clear whether these fluctuations in cGMP levels are a direct consequence of neurotransmitter function or are sequelae to other related events. The present study suggests that some neurons and many neuroglial cells are the major sites of cGMP in the cerebellum.

Animals↗
PubMed1978

[Concentration of acid and basic proteins in the nuclei of hippocampal neurons and neuroglia of rat brain following elaboration of a passive avoidance conditioned reflex].

By means of two-wave-length visible cytophotometry, the content of acidic and basic proteins per cell nucleus was shown to increase in CA3 hippocampal neurons only 3 hours after the learning session of conditioned reflex of passive avoidance. The protein content in the nuclei of perineuronal neuroglia cells of CA3 hippocampus increased only 6 hours after the learning session. Biochemical mechanisms dealing with the process of learning are discussed.

Animals↗
PubMed1979

[The perinatal neuroglia in hypoxia. An electron- and light microscopical study with addition Golgi's impregnation (author's transl)].

The light microscopical morphology of perinatal neuroglia caused by hypoxia was examined in 60 cases, in 5 of them corresponding structures were investigated electron microscopically. The astroglia was studied additional by using the silver impregnation technique Bubenaite in 20 cases of the group. The glial lipid accumulation is a perinatal pathological process and is not related to myelination. It was found in 71,5% of the cases in astroblasts and astrocytes but seldom in oligodendrocytes. At the ultrastructural level, the lipid-loaded neuroglial cells cannot be confused with macrophages. One third of the cases showed a proliferation of the macroglial. In 20% of the cases, a focal leukodystrophy was found. A hypoxical degeneration was revealed of astrocytes by the Golgi modification of Bubenaite. The study demonstrates pathological changes of myelin formation in connection with degeneration and immature myelination. These perinatal neuroglial reactions seem to be connected with diffuse leukodystrophies. The examination gives the impression that the oligodendroglial differentiation might be disturbed. In contrast to myelin degeneration, the glial cells lesions and myelination defects play a decisive role in postnatal CNS formation.

Astrocytes↗
PubMed1976

Potassium, neuroglia, and oxidative metabolism in central gray matter.

Reviewed is the author's investigation of potassium in extracellular fluid of cerebral neocortex and spinal cord determined with ion-selective microelectrodes, and of oxidative metabolism monitored by fluorometric determination of intramitochondrial NADH in intact cortex. When gray matter is excited by afferent input, or by direct electrical stimulation, the logarithm of the rise of extracellular potassium concentration ([K+]0), the sustained shift of electrical potential, and the response of oxidative metabolism are linearly correlated. However, during seizures and during spreading depression, the correlation is broken, suggesting that the demand for oxidative energy exceeds that corresponding to the elevation of [K+]0. There exists a critical concentration of [K+]0 at which spreading depression inevitably erupts (12 mM for cat cerveau isole), but no such critical level could be detected for seizures. The rate of clearance of excess potassium from extracellular fluid is slower for high concentrations than for low; this rate is further slowed by the administration of phenobarbital, and possibly also of diphenylhydantoin. Changes of membrane potential of glia cells in the mammalian spinal cord can adequately be described by the Nernst equation.

Animals↗
PubMed1979

Patterns of neuroglial proliferation in spinal cord white matter following exposure to ionizing radiation.

X-irradiation temporarily decreases the proliferative activity of neuroglia in immature rat spinal cord. Later, the proliferative activity in these irradiated regions surpasses that noted in control rats. Areas adjacent to the irradiated region have a greater than normal percentage of labelled neuroglia and may also be a source of neuroglia which re-populate the irradiated zone.

Aging↗
PubMed1979

"In situ" variation of folic acid and dihydrofolate reductase in the caudate nucleus in the ageing process.

In bovine caudate nucleus of young animal, a folic acid-positive reaction was found in the perikarya and in the neuroglia in parallel with a high dihydrofolate reductase activity in the nerve cells. In old animals, folic acid increased in neurons, neuroglia and some nerve cell processes; the folate enzyme was markedly decreased in neurons and increased neuroglia NADH2-cytochrom-C-reductase activity was strongly positive in nerve cells in young and old animals.

Aging↗
PubMed1975

A quantitative electron microscopic study of atypical structures in normal human cerebral cortex.

Biopsy samples of the cerebral cortex from four normal human brains were examined in the electron microscope for the presence of abnormalities related to neurones and neuroglia. Atypical forms of axons, axon terminals and dendrites, many of them similar to those described in a variety of pathological and experimental material, were found to occur in small but appreciable numbers. Neuroglia exhibiting atypical inclusions occurred but were much less common. Physiologically altered neuronal perikarya were not encountered apart from one neuronal death. An area of 3.6 x 10(5) mu2 was scanned from each brain and atypical structures were categorised and counted. The possible implications of the presence of these structures in normal brain in discussed and the need for neuropathologists and neuroanatomists to be aware of the existence of atypical forms of neuronal processes in normal human and animal brains is emphasised.

Adolescent↗