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Darwish M, Hattori S, Nishizono H, Miyakawa T, Yachie N, Takao K. Comprehensive behavioral analyses of mice with a glycine receptor alpha 4 deficiency. Mol Brain 2023; 16:44. [PMID: 37217969 DOI: 10.1186/s13041-023-01033-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
Glycine receptors (GlyRs) are ligand-gated chloride channels comprising alpha (α1-4) and β subunits. The GlyR subunits play major roles in the mammalian central nervous system, ranging from regulating simple sensory information to modulating higher-order brain function. Unlike the other GlyR subunits, GlyR α4 receives relatively little attention because the human ortholog lacks a transmembrane domain and is thus considered a pseudogene. A recent genetic study reported that the GLRA4 pseudogene locus on the X chromosome is potentially involved in cognitive impairment, motor delay and craniofacial anomalies in humans. The physiologic roles of GlyR α4 in mammal behavior and its involvement in disease, however, are not known. Here we examined the temporal and spatial expression profile of GlyR α4 in the mouse brain and subjected Glra4 mutant mice to a comprehensive behavioral analysis to elucidate the role of GlyR α4 in behavior. The GlyR α4 subunit was mainly enriched in the hindbrain and midbrain, and had relatively lower expression in the thalamus, cerebellum, hypothalamus, and olfactory bulb. In addition, expression of the GlyR α4 subunit gradually increased during brain development. Glra4 mutant mice exhibited a decreased amplitude and delayed onset of the startle response compared with wild-type littermates, and increased social interaction in the home cage during the dark period. Glra4 mutants also had a low percentage of entries into open arms in the elevated plus-maze test. Although mice with GlyR α4 deficiency did not show motor and learning abnormalities reported to be associated in human genomics studies, they exhibited behavioral changes in startle response and social and anxiety-like behavior. Our data clarify the spatiotemporal expression pattern of the GlyR α4 subunit and suggest that glycinergic signaling modulates social, startle, and anxiety-like behaviors in mice.
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Affiliation(s)
- Mohamed Darwish
- Department of Behavioral Physiology, Graduate School of Innovative Life Science, University of Toyama, Toyama, Japan
- Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Satoko Hattori
- Division of Systems Medical Science, Center for Comprehensive Medical Science, Fujita Health University, Aichi, Toyoake, Japan
| | - Hirofumi Nishizono
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa, Japan
| | - Tsuyoshi Miyakawa
- Division of Systems Medical Science, Center for Comprehensive Medical Science, Fujita Health University, Aichi, Toyoake, Japan
| | - Nozomu Yachie
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
- School of Biomedical Engineering, The University of British Columbia, Vancouver, Canada
| | - Keizo Takao
- Department of Behavioral Physiology, Graduate School of Innovative Life Science, University of Toyama, Toyama, Japan.
- Department of Behavioral Physiology, Faculty of Medicine, University of Toyama, Toyama, Japan.
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan.
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