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Published in: Brain Structure and Function 6/2020

Open Access 01-07-2020 | Schizophrenia | Original Article

Glutamic acid decarboxylase 67 haplodeficiency in mice: consequences of postweaning social isolation on behavior and changes in brain neurochemical systems

Authors: Sven Nullmeier, Christoph Elmers, Wolfgang D’Hanis, Kiran Veer Kaur Sandhu, Oliver Stork, Yuchio Yanagawa, Patricia Panther, Herbert Schwegler

Published in: Brain Structure and Function | Issue 6/2020

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Abstract

Reductions of glutamate acid decarboxylase (GAD67) and subsequent GABA levels have been consistently observed in neuropsychiatric disorders like schizophrenia and depression, but it has remained unclear how GABAergic dysfunction contributes to different symptoms of the diseases. To address this issue, we investigated male mice haplodeficient for GAD67 (GAD67+/GFP mice), which showed a reduced social interaction, social dominance and increased immobility in the forced swim test. No differences were found in rotarod performance and sensorimotor gating. We also addressed potential effects of social deprivation, which is known, during early life, to affect GABAergic function and induces behavioral abnormalities similar to the symptoms found in psychiatric disorders. Indeed, social isolation of GAD67+/GFP mice provoked increased rearing activity in the social interaction test and hyperlocomotion on elevated plus maze. Since GABA closely interacts with the dopaminergic, serotonergic and cholinergic neurotransmitter systems, we investigated GAD67+/GFP and GAD67+/+ mice for morphological markers of the latter systems and found increased tyrosine hydroxylase (TH)-IR fiber densities in CA1 of dorsal hippocampus. By contrast, no differences in numbers and densities of TH-positive neurons of the midbrain dopamine regions, serotonin (5-HT) neurons of the raphe nuclei, or choline acetyltransferase (ChAT)-expressing neurons of basal forebrain and their respective terminal fields were observed. Our results indicate that GAD67 haplodeficiency impairs sociability and increases vulnerability to social stress, provokes depressive-like behavior and alters the catecholaminergic innervation in brain areas associated with schizophrenia. GAD67+/GFP mice may provide a useful model for studying the impact of GABAergic dysfunction as related to neuropsychiatric disorders.
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Metadata
Title
Glutamic acid decarboxylase 67 haplodeficiency in mice: consequences of postweaning social isolation on behavior and changes in brain neurochemical systems
Authors
Sven Nullmeier
Christoph Elmers
Wolfgang D’Hanis
Kiran Veer Kaur Sandhu
Oliver Stork
Yuchio Yanagawa
Patricia Panther
Herbert Schwegler
Publication date
01-07-2020
Publisher
Springer Berlin Heidelberg
Keyword
Schizophrenia
Published in
Brain Structure and Function / Issue 6/2020
Print ISSN: 1863-2653
Electronic ISSN: 1863-2661
DOI
https://doi.org/10.1007/s00429-020-02087-6

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