Radial glia: what is it and what are its functions in the brain?
This group of nerve cells plays a fundamental role in the functioning of the brain.
Thinking about the brain or the nervous system in general is equivalent to thinking about neurons. The neuron is the basic unit of the nervous system, which is why we tend to focus on neurons when exploring the functioning of the nervous system. But there are not only neurons in the brain. We can also find glial cells, which support, protect and keep neurons alive. Among the multiple types of glial cells that we can find, in this article we are going to focus on the so-called glial cells. we are going to focus on the so-called radial glia, an essential element for our development.an essential element for our development.
What are glial cells?
Glia or glial cells are understood as a group of cells derived from the embryonic epithelium that cover the nervous system and form a network of support, protection, nutrition and maintenance of neurons. Initially it was believed that they were a substance that only kept neurons together, although this hypothesis was rejected after the discovery of the existence of synapses.
Its functions are multiple: in addition to contributing to providing structure to the nervous system, it has been observed that it is glial cells that bring neurons into interaction with the cells of the cerebrovascular system, acting as a filter. This means that the glia can provide nutrients and oxygen to the neurons.This refers to one of its main and most relevant roles: that of providing nutrients and keeping the nervous system alive. One last particularly relevant role of this cell type is the fact that they remove waste and maintain stability in the environment in which the neurons are located.
But although they were traditionally considered primarily as sustainers, recent research proposes that they are capable both of capturing and releasing information-transmitting substances with possible influence on synaptic transmission between neurons. synaptic transmission that occurs between neurons. Thus, they have an effect on information processing beyond mere neuronal sustenance.
Glial cells are essential for the proper functioning and survival of the nervous system. But the term glia includes a large number of cell types. Among them we can find astrocytes, oligodendrocytes, Schwann cells or the one that concerns us in this article, the radial glia.
Radial glia: basic elements
With regard to radial glia, we are dealing with a type of glial cell that is generally a type of glial cell of generally bipolar morphology that extends throughout the cerebral cortex and cerebellar (although in the latter case there are more elongations, being multipolar). These cells serve as structural pillars and contribute to the development of the nervous system.
They have often been linked to another type of glial cell, the astrocytes, because they play roles typical of this type of glial cell and, like them, have similar cytoskeleton and membrane proteins (possessing among others glutamate or GABA receptors). In fact, radial glia can become or derive into these.
Radial glia, also called aldainoglia, are mainly known for serving as a pathway or guide for neurons during pathway or guide for neurons during fetal development.. Such guidance occurs due to the interaction of glia and neurons, through a process of chemical attraction and the role of glia in promoting the growth and migration of nerve fibers.
However, this role is reduced with the passage of time: once the migration of neurons from the cortex to their final position has occurred and once new neurons are no longer born in most areas of the nervous system, its role becomes centered on supporting the neuronal network.
Its most important and well-known functions
Radial glia fulfill different roles within the organism, but the most prominent, researched and known of all of them we have already mentioned above: it is the type of cell that enables and acts as a guide for neurons during neuronal migration.The process is especially visible during fetal development, as newly formed neurons travel through the glial cells, using them as a guide to the cortex.
This process is especially visible during fetal development, as newly formed neurons travel through glial cells, using them as a guide to the cortex. Although this is not the only method of neuronal migration available, it is the best known and most common, especially with regard to the cerebral cortex.
In addition to this guiding and transport function, radial glia have also been implicated in the generation has also been related to neuronal generation and synthesis itself.It has been observed that they can act as progenitors of other cells such as neurons. Such neurogenesis is especially linked to infancy, but its involvement in the birth of new nerve cells in the adult brain is suspected in the few areas where it has been detected (in the hippocampus and olfactory bulb is where it has been observed the most). Likewise, they have been related to the recovery of some functions after the presence of brain lesions, and their link with processes such as synaptic and neuronal pruning that occurs during growth has been observed.
It has been shown that glial cells also play a very important role in the a very important role in generating a complex, functional and stable cerebrovascular network in the brain, and inThe glial cells have also been shown to play a very important role in generating a complex, functional and stable cerebrovascular network in the brain, especially early in life but also throughout the life cycle. In experiments with mice it was observed that their inhibition generates a degradation of the cerebral vascularization network and brain metabolism, something that greatly facilitates the appearance of neurodegeneration (something that is in fact discussed as an implication in diseases such as Alzheimer's).
Finally, it is worth mentioning that like the rest of glial cells, radial glia also play an important role in sustaining and keeping the surrounding neurons alive, facilitating their growth and nourishing them.
Bibliographic references
- Allen, N. J. and B. A. Barres (2009). Glia - more than just brain glue. Nature, 457: 675-677.
- Malatesta, P. & Götz, M. (2013). Radial glia: from boring cables to stem cell stars. Developments, 140: 483-486. The Company of Biologists Ltd.
- Rakic, P. (1972). Mode of cell migration to the superficial layers of fetal monkey neocortex. Journal of Compared Neurology, 145: 61-83.
(Updated at Apr 14 / 2024)