Role of Neuroglia in Health and Disease
Role of Neuroglia in Health and Diseases
Emerging evidence in both vertebrates and invertebrates is redefining glia as active players in the development and integrity of the nervous system. The formation of functional neuronal circuits requires the precise addition of new synapses. Mounting evidence implicates glial function in synapse remodelling and formation. However, the precise molecular mechanisms governing these functions are poorly understood. My thesis work begins to define the molecular mechanisms by which glia communicate with neurons at the Drosophila neuromuscular junction (NMJ) (Dayan, 2001). During development glia play a critical role in remodelling neuronal circuits in the Central Nervous System (CNS). In order to understand how glia remodels synapses, I manipulated a key component of the glial engulfment machinery, Draper. I found that during normal neuromuscular junction growth presynaptic boutons (terminals) constantly shed membranes or debris. However, a loss of Draper resulted in an accumulation of debris and ghost boutons, which inhibited synaptic growth. I found that glia use the Draper pathway to engulf these excess membranes to sculpt synapses. Surprisingly, I found that muscle cells function as phagocyte cells as well by eliminating immature synaptic ghost boutons. This demonstrates that the combined efforts of glia and muscle are required for the addition of synapses and proper growth (Bangfu, 2008). Neuroglia (neuron - a neuron, glia - glue) - is supporting a very important part of the nervous tissue associated with neurons genetically, morphologically and functionally. Glia cells do not conduct nerve impulses, but they carry the support of the nervous tissue, protective and insulating function. In addition, the pineal gland and the pituitary gland of the brain, which are not observed neurons, neuroglia is the bulk of these bodies and perform the secretary function (Sanes, 2006, pp. 3–4). The role of neuroglial activation and neuroinflammation are still uncertain but could be critical in maintaining, if not also in initiating, some of the CNS abnormalities present in autism. A better understanding of the role of neuroinflammation in the pathogenesis of autism may have important clinical and therapeutic implications (Dayan, 2001). Neuroglia, as already indicated, in its origin is divided into macroglia and microglia. Macroglia, as well as neurons that arise from the ectoderm, and mesoderm develop from microglia and is derived mesenchyme. The structure consists of macroglia ependyma, astroglia and oligodendroglia (Sanes, 2006, pp. 3–4). The most ancient type of macroglia is the ependyma (ependyma - upper garment). Ependyma is best developed in lower vertebrates, as well as in higher vertebrates during early development of the nervous system, during cell differentiation of the neural tube (Purves, 2001). At this stage of development of higher vertebrates ependimotisity plays the role of the structures that line the brain and restrict the cavity. In addition, ependimotsity act as support structures, as their processes form the framework, or stroma, in the intervals of which are developing neurons. In lower vertebrates, these structural and functional features of ependyma persist throughout ontogeny and in humans and higher vertebrates support functions continue to take on other cell macroglia, and ependyma lines the only, like the epithelium, cavity of the spinal canal and cavity of ventricles of the brain (Purves, 2001). Ependyma cells arranged in a row and have a prismatic or cubic form. They leave a cytoplasm process that goes into the radial nerve tissue, and ends with a slight thickening. Appendages connect with each other to form the outer border membrane bounding the cavity of the neural tube (Dayan, 2001).
Features of the regeneration of nerves
If the damage of the central nervous system...
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