Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity

In this article, we review studies of astrocytic-neuronal interactions and their effects on the activity of oxytocin (OXT) neurons within the magnocellular hypothalamo-neurohypophysial system. Previous work over several decades has shown that withdrawal of astrocyte processes increases OXT neuron ex...

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Main Authors: Yu-Feng Wang, Kathryn A. Hamilton
Format: Article
Language:English
Published: Wiley 2009-01-01
Series:The Scientific World Journal
Online Access:http://dx.doi.org/10.1100/tsw.2009.148
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author Yu-Feng Wang
Kathryn A. Hamilton
author_facet Yu-Feng Wang
Kathryn A. Hamilton
author_sort Yu-Feng Wang
collection DOAJ
description In this article, we review studies of astrocytic-neuronal interactions and their effects on the activity of oxytocin (OXT) neurons within the magnocellular hypothalamo-neurohypophysial system. Previous work over several decades has shown that withdrawal of astrocyte processes increases OXT neuron excitability in the hypothalamic supraoptic nucleus (SON) during lactation. However, chronically disabling astrocyte withdrawal does not significantly affect the functioning of OXT neurons during suckling. Nevertheless, acute changes in a cytoskeletal element of astrocytes, glial fibrillary acidic protein (GFAP), occur in concert with changes in OXT neuronal activity during suckling. Here, we compare these changes in GFAP and related proteins with chronic changes that persist throughout lactation. During lactation, a decrease in GFAP levels accompanies retraction of astrocyte processes surrounding OXT neurons in the SON, resulting from high extracellular levels of OXT. During the initial stage of suckling, acute increases in OXT levels further strengthen this GFAP reduction and facilitate the retraction of astrocyte processes. This change, in turn, facilitates burst discharges of OXT neurons and leads to a transient increase in excitatory neurochemicals. This transient neurochemical surge acts to reverse GFAP expression and results in postburst inhibition of OXT neurons. The acute changes in astrocyte GFAP levels seen during suckling likely recur periodically, accompanied by rhythmic changes in glutamate metabolism, water transport, gliotransmitter release, and spatial relationships between astrocytes and OXT neurons. In the neurohypophysis, astrocyte retraction and reversal with accompanying GFAP plasticity also likely occur during lactation and suckling, which facilitates OXT release coordinated with its action in the SON. These studies of the dynamic interactions that occur between astrocytes and OXT neurons mediated by GFAP extend our understanding of astrocyte functions within the central nervous system.
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spelling doaj-art-91874d9a89684a83a70edcebf30cfbe62025-08-20T03:20:36ZengWileyThe Scientific World Journal1537-744X2009-01-0191308132010.1100/tsw.2009.148Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein PlasticityYu-Feng Wang0Kathryn A. Hamilton1Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, USADepartment of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, USAIn this article, we review studies of astrocytic-neuronal interactions and their effects on the activity of oxytocin (OXT) neurons within the magnocellular hypothalamo-neurohypophysial system. Previous work over several decades has shown that withdrawal of astrocyte processes increases OXT neuron excitability in the hypothalamic supraoptic nucleus (SON) during lactation. However, chronically disabling astrocyte withdrawal does not significantly affect the functioning of OXT neurons during suckling. Nevertheless, acute changes in a cytoskeletal element of astrocytes, glial fibrillary acidic protein (GFAP), occur in concert with changes in OXT neuronal activity during suckling. Here, we compare these changes in GFAP and related proteins with chronic changes that persist throughout lactation. During lactation, a decrease in GFAP levels accompanies retraction of astrocyte processes surrounding OXT neurons in the SON, resulting from high extracellular levels of OXT. During the initial stage of suckling, acute increases in OXT levels further strengthen this GFAP reduction and facilitate the retraction of astrocyte processes. This change, in turn, facilitates burst discharges of OXT neurons and leads to a transient increase in excitatory neurochemicals. This transient neurochemical surge acts to reverse GFAP expression and results in postburst inhibition of OXT neurons. The acute changes in astrocyte GFAP levels seen during suckling likely recur periodically, accompanied by rhythmic changes in glutamate metabolism, water transport, gliotransmitter release, and spatial relationships between astrocytes and OXT neurons. In the neurohypophysis, astrocyte retraction and reversal with accompanying GFAP plasticity also likely occur during lactation and suckling, which facilitates OXT release coordinated with its action in the SON. These studies of the dynamic interactions that occur between astrocytes and OXT neurons mediated by GFAP extend our understanding of astrocyte functions within the central nervous system.http://dx.doi.org/10.1100/tsw.2009.148
spellingShingle Yu-Feng Wang
Kathryn A. Hamilton
Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity
The Scientific World Journal
title Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity
title_full Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity
title_fullStr Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity
title_full_unstemmed Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity
title_short Chronic vs. Acute Interactions between Supraoptic Oxytocin Neurons and Astrocytes during Lactation: Role of Glial Fibrillary Acidic Protein Plasticity
title_sort chronic vs acute interactions between supraoptic oxytocin neurons and astrocytes during lactation role of glial fibrillary acidic protein plasticity
url http://dx.doi.org/10.1100/tsw.2009.148
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AT kathrynahamilton chronicvsacuteinteractionsbetweensupraopticoxytocinneuronsandastrocytesduringlactationroleofglialfibrillaryacidicproteinplasticity