title: Distribution of immunoreactive glutamine synthetase in the adult human and mouse brain. Qualitative and quantitative observations with special emphasis on extra-astroglial protein localization.
abstract: Glutamine synthetase catalyzes the ATP-dependent condensation of ammonia and glutamate to form glutamine, thus playing a pivotal role in glutamate and glutamine homoeostasis. Despite a plethora of studies on this enzyme, knowledge about the regional and cellular distribution of this enzyme in human brain is still fragmentary. Therefore, we mapped fourteen post-mortem brains of psychically healthy individuals for the distribution of the glutamine synthetase immunoreactive protein. It was found that glutamine synthetase immunoreactivity is expressed in multiple gray and white matter astrocytes, but also in oligodendrocytes, ependymal cells and certain neurons. Since a possible extra-astrocytic expression of glutamine synthetase is highly controversial, we paid special attention to its appearance in oligodendrocytes and neurons. By double immunolabeling of mouse brain slices and cultured mouse brain cells for glutamine synthetase and cell-type-specific markers we provide evidence that besides astrocytes subpopulations of oligodendrocytes, microglial cells and neurons express glutamine synthetase. Moreover, we show that glutamine synthetase-immunopositive neurons are not randomly distributed throughout human and mouse brain, but represent a subpopulation of nitrergic (i.e. neuronal nitric oxide synthase expressing) neurons. Possible functional implications of an extra-astrocytic localization of glutamine synthetase are discussed.
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany. Electronic address: Hans-Gert.Bernstein@med.ovgu.de.
authors: Hans-Gert
authors: HG
authors: Bernstein
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany.
authors: Jana
authors: J
authors: Bannier
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany.
authors: Gabriela
authors: G
authors: Meyer-Lotz
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany.
authors: Johann
authors: J
authors: Steiner
authors: Institute of Biochemistry and Cell Biology, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany.
authors: Gerburg
authors: G
authors: Keilhoff
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany.
authors: Henrik
authors: H
authors: Dobrowolny
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
authors: Martin
authors: M
authors: Walter
authors: Department of Psychiatry, Otto-von-Guericke University, Faculty of Medicine, Magdeburg, Germany.
authors: Bernhard
authors: B
authors: Bogerts
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000201:enzymology*; D001921:Brain / Q000201:enzymology*; D002102:Cadaver; D005260:Female; D005974:Glutamate-Ammonia Ligase / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D009474:Neurons / Q000201:enzymology*; D009836:Oligodendroglia / Q000201:enzymology*
chemical_list: D005974:Glutamate-Ammonia Ligase
keywords: Astrocytes; Cell culture; Glutamine synthetase immunohistochemistry; Mouse brain; Neurons; Oligodendrocytes; Post-mortem human brain