Astrocytes of the early postnatal brain. (30th May 2020)

• Record Type: Journal Article
• Authors: Felix, Lisa; Stephan, Jonathan; Rose, Christine R.
• Other Names: Majewska Ania guestEditor.; Verkhratsky Alexej guestEditor.; Hughes Ethan guestEditor.
• Is Part Of: European journal of neuroscience. Volume 54:Number 5(2021)
• Page Start: 5649
• Page End: 5672
• Publication Date: 2020-05-30
• Subjects: calcium -- extracellular potassium -- forebrain -- glutamate transport -- mouse; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.14780
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: In the rodent forebrain, the majority of astrocytes are generated during the early postnatal phase. Following differentiation, astrocytes undergo maturation which accompanies the development of the neuronal network. Neonate astrocytes exhibit a distinct morphology and domain size which differs to their mature counterparts. Moreover, many of the plasma membrane proteins prototypical for fully developed astrocytes are only expressed at low levels at neonatal stages. These include connexins and Kir4.1, which define the low membrane resistance and highly negative membrane potential of mature astrocytes. Newborn astrocytes moreover express only low amounts of GLT‐1, a glutamate transporter critical later in development. Furthermore, they show specific differences in the properties and spatio‐temporal pattern of intracellular calcium signals, resulting from differences in their repertoire of receptors and signalling pathways. Therefore, roles fulfilled by mature astrocytes, including ion and transmitter homeostasis, are underdeveloped in the young brain. Similarly, astrocytic ion signalling in response to neuronal activity, a process central to neuron–glia interaction, differs between the neonate and mature brain. This review describes the unique functional properties of astrocytes in the first weeks after birth and compares them to later stages of development. We conclude that with an immature neuronal network and wider extracellular space, astrocytic support might not be as demanding and critical compared to the mature brain. The delayed differentiation and maturation of astrocytes in the first postnatal weeks might thus reflect a reduced need for active, energy‐consuming regulation of the extracellular space and a less tight control of glial feedback onto synaptic transmission. Abstract : Astrocytes in the neonate forebrain exhibit a less complex morphology than mature cells, and proteins prototypical for fully developed astrocytes such as connexins, Kir4.1 and transmitter carriers are only expressed at low levels. Moreover, properties of intracellular Ca 2+ signalling differ in neonates. The reduced astrocytic control of ion and transmitter homeostasis in the young brain might be compensated for by less demanding neuronal network and a wider extracellular space.