Glial cells between neurons

An emerging area of interest for the physiological action of the brain of chanokine is the intercellular communication system between neuronal and ghal cells. Indeed, recent in vitro and in situ studies indicated that the chemokines together with then-receptors are constitutively expressed by glial cells and neurons in mature brain (Asensio and Campbell 1999 Cho and Miller 2002 Tran and Miller 2003 Rostene... 

Carnosine can affect gene expression. Ikeda et al. (1999) showed that carnosine markedly upregulates vimentin synthesis in cultured rat fibroblasts, while an association between carnosine and vimentin, a cytoskele-tal, intermediate filament protein has been noted in glial cells and neurons (Bonfanti et al., 1999). Interestingly, it has also been shown that the protease, oxidized protein hydrolase (OPH), is coexpressed with vimentin in COS cells (Shimizu et al., 2004). Thus, it is at least possible that carnosine could induce synthesis of OPH in the cultured human fibroblasts and thereby increase the cellular ability to eliminate oxidized... 

Our knowledge of myelin constituents has greatly increased, as well as the role of a bidirectional dialogue between glial cells and neurons in myelination and demyeli-nation but, little is known of the mechanisms responsible for myelin repair. Why is remyelination incomplete with less myelin and shorter intemodes ... 

AU mental activity is achieved by two types of cells, neurones and glial cells, and approximately 50 different chemicals that provide communication between the neurones. The neurones are specialised cells that generate differences in electrical potential that are transmitted along their surface to carry information. Within the brain, integration and coordination is brought about by around 10" neurones, com-... 

Figure 14.4 Different types of glial cells. Astrocytes connect capillaries and neurones. Fibrous astrocytes, with less branching and more filamentous processes, occur mainly in white matter while protoplasmic astrocytes are located principally in the grey matter. Oligodendrocytes form the myelin sheath by wrapping themselves around axons. The connection between the myelin sheath and the oligodendrocyte is permanent and provides material for the myelin sheath. Microgliocytes (microglia) are the phagocytes of the nervous system. The ciliated ependymal cells line the cavities of the central nervous system.

In the CNS, glial cells aid in the communication between the densely packed neurons of the CNS. These cells also play a big part in forming the blood-brain barrier. The blood-brain barrier keeps some classes of chemicals from entering the brain, which can make it very difficult to treat diseases of the brain. However, some chemicals, such as caffeine, readily enter the brain, as do many other neuroactive compounds. Compounds essential for function are actively transported across this barrier. 

A third tissue is muscle, which is classified into three types striated (voluntary skeletal muscle), cardiac (involuntary striated muscle), and smooth (involuntary) muscle. There are two major groups of cells in nervous tissue, the fourth tissue type. Neurons are the actual conducting cells whose cell membranes carry nerve impulses. Several kinds of glial cells lie between and around the neurons. 

In addition to neurons, the brain contains 5-10 times as many glial cells of several types. Tire neuroglia occupy 40% of the volume of brain and spinal cord in the human. Some glial cells seem to bridge the space between neurons and bloodcarrying capillaries. Others synthesize myelin. Some are very irregular in shape. 

Glutamate-Related Metabolic Interactions Between Neurons and Glial Cells... 

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