New Insights into Neuron-Glia Communication
There is an intimate relationship that we must pay more attention in our research: the dialogue neuron-glia; the cross-talk between microglia and neuron help us. This expanded relationship between neurons and glia is challenging traditional neurobiology. Contrary to dogma, some neurons in the central nervous system. Apparently, there are reciprocal relationships between neurons and glial cells ( Fig. 1). Nociceptive inputs related to injury are carried by primary afferent nerves .
However, the supporting evidence was comparatively meager because glia have been studied with tools used to probe the electrical excitability of neurons. Although many of the same voltage-sensitive ion channels and neurotransmitter receptors of neurons are found in glia 1glial cells lack the membrane properties required to fire action potentials. Nevertheless, these ion channels and electrogenic membrane transporters allow glia to sense indirectly the level of neuronal activity by monitoring activity-dependent changes in the chemical environment shared by these two cell types.
Advanced imaging methods, which allow observation of changes in intracellular and extracellular signaling molecules in real time, show that glia communicate with one another and with neurons primarily through chemical signals rather than electrical signals see Movie S1.
Many of these signaling systems overlap with the neurotransmitter signaling systems of neurons, but some are specialized for glial-glial and neuron-glial communication. This expanded relationship between neurons and glia is challenging traditional neurobiology.
Glia - Wikipedia
Contrary to dogma, some neurons in the central nervous system CNS use rapid neurotransmission not only at synapses with other neurons, but also at synapses with glia as well. Furthermore, neural activity releases chemical messengers not only at synaptic junctions, but also in extrasynaptic regions of neurons. This suggests functions for neuron-glial communication beyond those associated with synaptic transmission.
- New Insights into Neuron-Glia Communication
- Neuroscience for Kids
For example, glia can regulate synapse formation, can control synaptic strength, and may participate in information processing by coordinating activity among sets of neurons. Conversely, neural impulse activity regulates a wide range of glial activities, including their proliferation, differentiation, and myelination.
Glial Cells There are three categories of glia: Schwann cells and oligodendrocytes—the myelin-forming cells of the peripheral nervous system PNS and CNS, respectively, that wrap layers of myelin membrane around axons to insulate them for impulse conduction—and astrocytes, which are closely associated with neurons in the brain but do not form myelin Fig.
Astrocytes ensheath synaptic junctions, associate with nodes of Ranvier, and respond to disease and injury by clearing cellular debris, secreting trophic factors and forming scars. The view is based on the general deficiency of the mature nervous system in replacing neurons after an injury, such as a stroke or trauma, while very often there is a profound proliferation of glia, or gliosis near or at the site of damage.
However, detailed studies found no evidence that 'mature' glia, such as astrocytes or oligodendrocytesretain the ability of mitosis. Only the resident oligodendrocyte precursor cells seem to keep this ability after the nervous system matures. On the other hand, there are a few regions in the mature nervous system, such as the dentate gyrus of the hippocampus and the subventricular zonewhere generation of new neurons can be observed.
By contrast, scientific understanding of whether neurons are permanently post-mitotic or capable of mitosis,    is still developing.
In the past, glia had been considered[ by whom? For example, glial cells were not believed to have chemical synapses or to release transmitters.
Neuron, Glia and Reciprocal Relationships in Pain Processing
They were considered to be the passive bystanders of neural transmission. However, recent studies have shown this to be untrue. Others regulate the internal environment of the brain, especially the fluid surrounding neurons and their synapsesand nutrify neurons.
During early embryogenesisglial cells direct the migration of neurons and produce molecules that modify the growth of axons and dendrites. Neuron repair and development[ edit ] Glia are also crucial in the development of the nervous system and in processes such as synaptic plasticity and synaptogenesis.
Glia have a role in the regulation of repair of neurons after injury. In the central nervous system CNSglia suppress repair. Glial cells known as astrocytes enlarge and proliferate to form a scar and produce inhibitory molecules that inhibit regrowth of a damaged or severed axon.
In the peripheral nervous system PNSglial cells known as Schwann cells promote repair. After axonal injury, Schwann cells regress to an earlier developmental state to encourage regrowth of the axon. For example, a spinal cord may be able to be repaired following injury or severance.
Schwann cells are also known as neuri-lemmocytes. These cells envelop nerve fibers of the PNS by winding repeatedly around a nerve fiber with the nucleus inside of it.
This process creates a myelin sheath, which not only aids in conductivity but also assists in the regeneration of damaged fibers.