Neuroglia


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neuroglia

[nu̇′räg·lē·ə]
(neuroscience)
The nonnervous, supporting elements of the nervous system.

Neuroglia

 

(also glia), the group of interstitial cells whose cell bodies and outgrowths fill the spaces in the brain and spinal cord between the capillary blood vessels and the nerve cells, or neurons.

Each neuron is surrounded by several neuroglial cells. The neuroglia is evenly distributed over the entire brain and accounts for approximately 40 percent of the brain’s volume. There are about 140 billion neuroglial cells within the mammalian central nervous system (CNS); they differ from neurons in size (neuroglial cells are three to four times smaller) and in morphological and biochemical characteristics. In contrast to neurons, the cells of the neuroglia retain the capacity to divide. This is why the number of neurons in the CNS decreases with age, while the number of neuroglial cells increases. The neuroglia acts as a protective layer for the neurons and forms part of the blood-brain barrier between the bloodstream and the encephalic neurons. This barrier regulates the passage of matter between the blood and the CNS. The neuroglia also helps to maintain the reactive properties of nerve tissue in such conditions as posttraumatic scarring, inflammatory reactions, and oncogenesis. The neuroglia comprises the astroglia (also called macroglia), oligoglia (also called oligodendroglia), and the ependyma. The microglia occupies a special position among neuroglial cells as the “scavenger” of the CNS.

Astrocytes (the cells of the astroglia) account for about 60 percent of the total number of neuroglial cells. They are star-shaped cells with numerous slender outgrowths that entwine the neurons and the walls of the capillary blood vessels. The astroglia regulates the water-salt metabolism of nervous tissue and is the principal element of the blood-brain barrier. About 25 to 30 percent of neuroglial cells are contained in the oligoglia. Oligodendrocytes (the cells of the oligoglia) are rounded cells with short outgrowths and are smaller than astrocytes. They surround the cell body and axon (the conducting portion) of a neuron. Oligodendrocytes are characterized by a highly active protein and nuclein metabolism and are also responsible for the transport of matter to the neurons. The myelin sheath that surrounds an axon mostly consists of oligodendrocytes. The ependyma consists of cylindrical cells that line the ventricles of the brain and the central lumen of the spinal cord. The ependyma is the barrier between the blood and cerebrospinal fluid and also appears to have a secretory function.

The neuroglia, especially the oligoglia, participates in the generation of the slow, spontaneous bioelectric activity that is characterized by α waves on an electroencephalogram. Neurons and neuroglial cells form a unified functional and metabolic complex that operates in cycles and has an adaptive function. The complex has the capacity to shift certain metabolic processes predominantly to the neuronal or to the neuroglial elements, depending on the nature and intensity of the physiological and pathological condition of the CNS.

REFERENCES

Hidden, H. “Kletki-satellity ν nervnoi sisteme.” In the collection Struktura i funktsiia kletki. Moscow, 1964. (Translated from English.)
Pevzner, L. Z. Funktsional’naia biokhimiia neiroglii. Leningrad, 1972.
Kuffler, S. W., and J. G. Nicholls. “The Physiology of Neuroglial Cells.” In the collection Ergebnisse der Physiologic, biologischen Chemie und experimentellen Pharmakologie, vol. 57. Berlin-Heidelberg-New York, 1966.

L. Z. PEVZNER

References in periodicals archive ?
Methods: Gene expression profiling was performed on the human neuroglia cell line T98G after treatment with APE, ESE, KJ and total number of more than two fold-deregulated genes from all experiments were compared by Venn diagram.
Conclusion: Analysis of RNA microarray data from isolated neuroglia cells and the comparison the number of genes deregulated by plant extracts and their fixed herbal formulation might be a useful tool/method for assessment of synergistic and antagonistic interactions of herbal extracts in human organism.
Methods: Gene expression profiling was performed using the T98G human neuroglia cell line after treatment with the Rhodiola rosea SHR-5 extract and several of its individual constituents (salidroside, triandrin and tyrosol).
In this study, we tested the effects of the Rhodiola SHR-5 extract and three isolated compounds, specifically salidroside, triandrin, and tyrosol, on the gene expression profiles of isolated human neuroglia cells, which were measured using m-RNA arrays.
gene expression profiles (Table 15) of isolated neuroglia cells,
2007), the down-regulation of some G-protein coupled receptors, particularly the serotonin receptors in isolated neuroglia cells (Panossian et al.
Investigations of the histology of the ganglia has shown that there are 3 types of cells: neurons (NR), neuroglia (NG), and neurosecretory (NS) cells.
The inner medulla is composed of nerve fibers and neuroglia.
The main method to be used was measuring the release of NPY and Hsp72 from neuroglia cells in response to treatment with various plant extracts using high throughput ELISA techniques.
Table 2 Effect of adaptogens, presumably adaprogens and other plants extracts on release of NPY and Hsp72 proteins from isolated human neuroglia cells.
The human neuroglia cell line T98G (ATCC, CRL-1690; Manassas, VA) has a hyperpentaploid chromosome count that was derived from a 61-year-old Caucasian male with glioblastoma multiforme.