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Farkas E, Szilvásy-Szabó A, Ruska Y, Sinkó R, Rasch MG, Egebjerg T, Pyke C, Gereben B, Knudsen LB, Fekete C. Distribution and ultrastructural localization of the glucagon-like peptide-1 receptor (GLP-1R) in the rat brain. Brain Struct Funct 2021; 226:225-245. [PMID: 33341919 PMCID: PMC7817608 DOI: 10.1007/s00429-020-02189-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 11/25/2020] [Indexed: 12/25/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) inhibits food intake and regulates glucose homeostasis. These actions are at least partly mediated by central GLP-1 receptor (GLP-1R). Little information is available, however, about the subcellular localization and the distribution of the GLP-1R protein in the rat brain. To determine the localization of GLP-1R protein in the rat brain, immunocytochemistry was performed at light and electron microscopic levels. The highest density of GLP-1R-immunoreactivity was observed in the circumventricular organs and regions in the vicinity of these areas like in the arcuate nucleus (ARC) and in the nucleus tractus solitarii (NTS). In addition, GLP-1R-immunreactive (IR) neuronal profiles were also observed in a number of telencephalic, diencephalic and brainstem areas and also in the cerebellum. Ultrastructural examination of GLP-1R-immunoreactivity in energy homeostasis related regions showed that GLP-1R immunoreactivity is associated with the membrane of perikarya and dendrites but GLP-1R can also be observed inside and on the surface of axon varicosities and axon terminals. In conclusion, in this study we provide a detailed map of the GLP-1R-IR structures in the CNS. Furthermore, we demonstrate that in addition to the perikaryonal and dendritic distribution, GLP-1R is also present in axonal profiles suggesting a presynaptic action of GLP-1. The very high concentration of GLP-1R-profiles in the circumventricular organs and in the ARC and NTS suggests that peripheral GLP-1 may influence brain functions via these brain areas.
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Affiliation(s)
- Erzsébet Farkas
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Anett Szilvásy-Szabó
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Yvette Ruska
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Richárd Sinkó
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | | | | | | | - Balázs Gereben
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | | | - Csaba Fekete
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Budapest, 1083, Hungary.
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, MA, 02111, USA.
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