Neuronal and glial cells

Fig. 8.3 Chemokines are neuromodulators. Some chemokines can be synthesized, as their own receptor, by the same neuron (a). A chemokine released by exocytosis can modulate the electrical activity of neurons after binding to its own presynaptic receptor (autoreceptor). Chemokines can also act on other neurons and glial cells (astrocytes and microgha) which express chemokine receptors (b). (Adapted from Rostene and Melik-Parsadaniantz, Pour la Science 2008, 369 66-72)...

Number of papers to date have shown that the CXCR4 receptors expressed in both neuronal and glial cells are functional and coupled to multiple intracellular pathways (Lazarini et al. 2003). The CXCR4 through pertussis toxin (PTX)- sensitive G proteins is coupled to at least two distinct signaling pathways (1) the first pathway, involving the activation of phosphatidylinositol- 3 (PI-3) kinase and extracellular signal... 

Hatoii K, Nagai A, Heisel R et al (2002) Eractalkine and fractalkine receptors in human neurons and glial cells. J Neurosci Res 69 418-426... 

These approaches to receptor identification and classification were, of course, pioneered by studies with peripheral systems and isolated tissues. They are more difficult to apply to the CNS, especially in in vivo experiments, where responses depend on a complex set of interacting systems and the actual drug concentration at the receptors of interest is rarely known. However, the development of in vitro preparations (acute brain slices, organotypic brain slice cultures, tissue-cultured neurons and acutely dissociated neuronal and glial cell preparations) has allowed more quantitative pharmacological techniques to be applied to the action of drugs at neurotransmitter receptors while the development of new recording methods such as patch-clamp... 

Beall, C., and Hirsh, J. (1987). Regulation of the Drosophila dopa decarboxylase gene in neuronal and glial cells. Genes Dev. 1 510-520. 

Tififany-Castiglioni E. 1993. Cell culture models for lead toxicity in neuronal and glial cells. Neurotoxicology 14 513-536. 

Rajkowska G. Postmortem studies in mood disorders indicate altered numbers of neurons and glial cells. Biol Psychiatry 2000. 

Ependymal cells abut layers of astrocytes, which in turn envelop neurons, neurites and vascular components. In addition to neurons and glial cells, such as astrocytes and oligodendrocytes, the normal CNS parenchyma contains blood vessels and microglial cells, the resident macrophages of the CNS. 

Cell adhesion molecules (CAMs) play critical roles in all facets of nervous system development and maintenance. Important phenomena in which CAMs are involved include initial formation of the neural tube and the neural crest, migration of all neurons and glial cells, axonal outgrowth and guidance, target selection, synaptic stabilization and plasticity, myelination and nerve regeneration after injury (see Chs 4,24,28-30 and 53). Adhesion molecules interact with each other and with nonadhesive cell-surface and/or cytoplasmic molecules, and, in the two... 

Trophic factors can also be supplied through less specific mechanisms. Growth factors are synthesized by a wide variety of cell types, including neurons and glial cells. 

Individual neurons and glial cells are responsive to a number of different growth factors. Growth factors play both unique and overlapping roles in the development and sustenance of these cells. Perhaps the most dramatic example of this is the elaborate array of trophic factors that have evolved to support spinal motor neurons. There are presently at least 15 different factors that are known to influence the survival of these cells [4]. 

Phospholipid molecules of membranes from neurons and glial cells store a wide variety of lipid messengers. Receptor-mediated events and changes in [Ca2+]i, such as occur during excitatory neurotransmission and activity-depen-dent synaptic plasticity, activate phospholipases that catalyze the release of bioactive moieties from phospholipids, which then participate in intra- and/or intercellular signaling pathways. 

Glucocorticoid. Adrenal steroid receptors have been subdivided into two categories, one of which is the classical glucocorticoid receptor [7,19]. This receptor, cloned from human and rat sources, consists of a steroid- and DNA-binding subunit of 95 kDa [7, 19]. Such receptors, which have dissociation constants of 4-5 nM for glucocorticoids, are widely distributed across brain regions and are found in neurons and glial cells [7,19]. 

Iversen, L. L. and Kelly, J. S. (1975) Uptake and metabolism of gamma-aminobutyric acid by neurones and glial cells. Biochem. Pharmacol. 24, 933-938. 

P450 reductase-dependent metabolism is active in both neuronal and glial cells and ubiquitously present among major brain structures of rat (Teissier et al., 1998). 

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